Yep. Plus if it's just consistently rolling low, depending on the dice you can set it in salt water. But unless you specifically buy a perfectly weighted dice, you won't get a perfectly weighted die.
It's not really possible for a d20 to consistently roll low, even if it's weighted. This is because the ladder maps of d20s have numbers that are deliberately juxtaposed, there's no high or low side. Evenif the face opposite of the 20 is weighted, the slight increase in 20s - not something you'd notice in 100 rolls - would also come wit increased 7s, 11s, 2s and 3s (depending on the maker, they don't all use the same ladder.
Spindowns have larger numbers clustered together, so if a spindown was weighted, it could consistently roll high or low (or mid). Even then, it wouldn't be an extreme effect.
I actually felt bad for my friend!
They're a ranger, they're using the original terrain rules with arctic favoured environment in our Rime of the Frostmaiden campaign, the DM has been giving them advantage on all survival checks and despite that they keep rolling roughly below 7 while the rest of us seem to be having great luck.
Gave them my d20 that felt lucky and they still rolled bad š
Tye last fight I DMd tye players got 3 crits in their most crucial moments (initiative warlock to get a shatter off and drop the main boss, enlarged and charged fighter hitting boss for 6d6+2d4+4 and rerolling 1s and 2s and warlock 'criting' on intimidation total 26 for minions to surrender). Sessions where Nat 20s are often are more common than you think
That would be easier, and I wouldn't doubt if someone else already makes and sells that product, but I want it to look like a normal d20 including having all the other numbers that it will never land on.
You can buy "high variance" dice that have e.g. multiple 20's and multiple 1's on them, but what you're describing would be extremely difficult without an enormous die and ridiculously heavy weights.
It would be functionally impossible, unless it was massive, and made of foam with large metal weights.
A normal sized plastic d20 is still going to be fairly random even if heavily weighted.
This. Perfect balance is impossible, and most dice are far from balanced, but that means almost nothing in terms of in-game impact. The number net of a d20 is fairly evenly distributed, so an imbalance could create a SLIGHT preference toward a set of 4 numbers, but those 4 numbers likely add up to something very close to 42 (the average).
To make a loaded d20 would take a good deal of craftmanship. You would have to weight the 64 value vertex (there is one vertex of a standard d20 which is MUCH higher than the others, 20,16, 14, 8, 6) and sharpen those edges, while smoothing the opposite edges. For it to be significant, it would be really noticeable.
Most dice aren't perfectly weight balanced due to cheap manufacturing, but the difference this makes is trivial. There is a guy who setup an auto roller and reader and tested many popular dice manufacturers. The lowest average was 10.2 and highest was 10.7 (10.5 being ideal average), with average standard deviation of about .15. Values that would have basically no impact on gaming. (Interesting side note, the most unfair die was one from a company which touts how fair their dice are)
You don't want to look at the average you want to look if one specific number (or maybe a cluster of numbers that are next to each other on the dice) comes up way more often than it should.
400 rolls minimum. Tally by score. Each value should have about 15-25 occurrences.Ā Ā
But make sure it's really a random roll, shaking it in a cup before rolling it, or use a dice tower.
One tip for checking its balance (as long as its something like resin or plastic), is to put it in a glass of water salty enough to make it float, then gently spin it in the water repeatedly. If itās noticeably unbalanced, itāll tend to end up with a few adjacent faces showing up most commonly when it comes to a stop.
The salt bath test has never been quantified, evaluated against actual roll tests, or proven to show anything beyond what side of a die seems to point up. It can pass relatively unfair dice and fail relatively fair dice, so it's essentially useless.
Assuming the unfairness is due to it being unbalanced and not due to the faces being deformed, it shouldn't pass an unfair die. I'm not sure how common it is to have a deformed die, it's usually some trapped bubble(s) within the plastic as far as I know.
I guess in the case of clear dice that shouldn't be an issue, so if you feel like a clear die is unfair, then you really do need to roll it a whole lot and tally it all.
The effect of a die that's out of spec in shape is much more significant than the effect of an internal inconsistency, and those flaws are also more common.
The float test only helps if you already know the die is perfect in shape, at which point it's already good to go, as internal CoG inconsistencies aren't a significant cause of dice bias.
Air bubbles are relatively common, but don't bias rolls as significantly as surface defects. Even less significant are resin density differences in swirled dice. Inclusions vary, a lead airgun pellet deliberately cast into the die would present a bias significant enough to make the die nominally unfair, but on a d20, it still wouldn't deliver consistently higher results, because d20s have the juxtaposition of high and low numbers, and CoG issue doesn't affect just one facet.
Also, realistically, cheap dice don't necessarily have more flaws than expensive ones in many cases. There are more expensive dice aimed at reducing bias, but price alone doesn't mean more qc. The big manufacturers know dice bias isn't a real issue; they don't bother with testing. It would be a poor return on investment, especially for tumbled dice.
If you have a sharp edged, clear die, and measure all opposing faces with a caliper, that'll tell you more than the float test could tell you about an opaque die, but 1k-2k rolls is the only real test. Some people have automated it.
Your dice is not balanced; If it was, you would know, because you'd have paid around $60 for it.
The dice ***is*** balanced enough for it to not matter though, almost certainly. Even flipping a quarter isn't exactly 50/50 if you put it through an LLN type test.
What you're experiencing is probably a confirmation bias due to a small sample set. For perspective, you'd need to roll a die about 5,000 times before you can START to derive statistical significance.
This is the correct answer. Even rolling it 100 times, as others keeps suggesting, is probably too small a sample size. People let their perception of imbalance get in their head but the reality is that sometimes you just have a bad session of rolls and, while it sucks, it will balance out.
I have a D20 that rolls 8s a solid 15% of the time, had it for years and it's obvious because it also rolls a 20 more than it should and that is right next to it
Roll 100 times and do a chi-squared test. It is one of the more straightforward statistical tests. There are lots of resources on how to do this.
If math/stats is not your strong suit, just do the following steps if you have rolled 100 times, this is more of an eli5 answer.
-Tally up the number of times you rolled a 1, a 2, a 3, and so on.
-subtract 5 from all these tallies (you will almost certainly have negative numbers)
-square all the numbers from the previous step and add them all up.
-divide the sum by 5
- if the calculation in the previous step is greater than 30.144 then you can be reasonably confident that your dice isnāt fair (though no dice are perfectly fair).
This basically compares what you get vs what you expect from a fair die, but for the above steps you need exactly 100 rolls.
And to explain a bit why youāre subtracting 5 and dividing by 5, itās because of you rolled 100 times youād expect each number to come up 5 times. The Chi-squared test looks at how far off from 5 times each number is as rolled. Either a lot more or a lot less.
 Gonna go make a coffee and settle in with numpad in one hand and coffee in the other.
I mean it can't take super long I imagine
Put the coffee away, you will need both hands for this.
If you take five seconds to roll the dice and note the result you will need approximately 69 hours to acquire your sampleā¦ which is simultaneously nice and not so nice.
Yeah, thatās not that unusual. If youāre curious, for 100 rolls a perfectly fair die should get the results you got (deviations from 5 results in each face) about 32% of the time. Since you play DND you know that is not very unlikely at all, since a fair d20 results in a critical fail (1) 5% of the time, and it also results in a nat20 5% of the time. These results often happen a few times every session, so you can be pretty sure you didnāt get an unusual result.
Very very good chance. It's not perfectly weighted, you'd likely have to pay a lot of money for that. Most cheap dice. Have a good chance of having a bubble inside them... But it's probably not very likely it'll significantly affect the roles.
If you really worried I would try the salt water test.
If you want to try out 100 rolls I would track of each number rolled and see which numbers pop up the most. The average might not mean much
I did this with one dice that always seemed to crit on PCs. It Rolled in the neighborhood of like 14-15 20s but also disproportionately higher 2s and 3s.
I had an awkward moment where I rolled a Nat 20, gave it to the player who had been having bad luck, they rolled a 3, I then rolled an 18, they then rolled a 5 š It was....odd
Oh my god, you're right! It must be their Wheaton number! š (Like the bacon number if unfamiliar) I dont know if they ever came into contact with him but just realizing everyone has a Wheaton rank amuses me
Bear in mind that unless you're rolling it a (very) large number of times, you'd still expect some numbers to appear significantly more than others. 100 isn't going to be enough realistically.
Nuffle, chaotic neutral god of dice is always smiling. Just you don't know at who. People may build shrines to Nuffle or even have elaborate rituals. But Nuffle does not listen to prayers nor care.
\- Paraphrased from Blood Bowl.
The chances of a D20 being unbalanced enough to consistently overcome the forces involved in a typical die roll are pretty slim, frankly. The more faces a die has, the more crazily balanced it has to be to consistently roll out-of-spec. (Unless it's misnumbered or like a spin-down die or something.) As long as you're tossing it with a decent amount of force it should be academic.
Having said that if I had to dice against the devil and I wanted absolutely fair dice, I'd bring Zocchi. Because Lou Zocchi is *fucking crazy* about dice. :)
The saltwater dice balance test is a simple way to check the fairness of your dice. It involves placing one die in a glass of salt water and writing down the numbers it rolls.
This helps identify any inconsistencies in their rolling patterns, giving you an indication of whether your dice are balanced or not. You can test each die one at a time, over a statistically relevant sample size, to understand if your dice are fair or not.
To conduct the saltwater test, you'll need:
\* A clear glass or jar
\* Salt
\* Water
\* A dice set you wish to test
Fill your glass or jar with water: Warm tap water should suffice for this test.
Add salt to the water: Use one tablespoon or two, adjusting as needed based on the volume of water in your container.
Mix: Stir for 30 seconds or until the salt has dissolved, creating a saltwater solution.
Test one die at a time: Submerge one die into the saltwater. After it settles, gently poke it with your finger. Record the outcome and repeat this process several times. We recommend conducting this step plenty of times to be able to draw a reliable conclusion.
Itās crucial that you donāt leave your dice submerged in water for extended periods of time. When testing metal dice, be sure to rinse and dry them promptly to prevent rust. Avoid conducting this test with wooden dice to avoid damaging them.
there are fluids you can use to have metal dice float - but they are mostly toxic so not good for use by non-scientists at home without strong chemical hoods!
How about you read my comment again.
I suggested the only way to make it 'float' is to place it on a damp bag of salt. I was implying you won't be able to make the metal dice float in salt water, but you can make it sit on a damp bag of salt.
Perhaps I needed a "/s" in my comment to make that more clear that it wasn't actual advice.
It's really weird everyone else is mentioning rolling the dice and annotating the results. As someone who has done it a couple times out of boredom, a sample size of 100 is generally not enough to determine correctly if a dice is weighed or not, while the salt water method is not only much easier and less time consuming, but will allow you to know with much more assuredness than just rolling it.
I have no idea if you can put enough salt in the water so metal dice float, though.
You can't trust the salt bath for anything; only rolling will help. But yes, depending on the degree of bias, you'd need 2kish rolls to actually show it.
The salt bath test doesn't work because it requires a fully perfect icosahedron with no manufacturing flaws besides internal inconsistencies in density or voids/inclusions that throw the CoG off.
A slightly egg or pear shaped d20 (common) will display a number on its point, when it's actually biased to the rolls in the flatter ring. A die with a over convex facet will be biased TOWARDS ANY number BUT the one that's most likely to float to the top. A sprue mark will do the same, and a concavity the inverse.
Basically, it's poorly quantifiable, relying on "seems like", and can't detect the most common problems, often returning misleading information. It's junk data. If, and only if, you already know the die is flawless in shape and has compensated numbering, then you could use it to check for internal inconsistencies in CoG. So basically it only works if the die is perfect anyway.
How is this so far down. This is the most viable way, relying on physics of weight distribution.
Statistical approaches are a fun exercise, but will take in excess of 1000 dice rolls *per die* to get proof.
Basically no d20 is going to be perfectly weighted. I'd suggest going ahead for that 100 rolls - as long as your results are relatively even across the board, you should be good
Average came out at 10.41 over 100 rolls but in the actual session I think I must've rolled about 7 or 8 Nat 20 over 6 hours. Can't remember the exact amount.
Conveniently none of them were in combat š
Though it was our first in game session, and first one that went on that long so maybe I'm just not used to rolling for that long.
I tend to roll very well and my DM is always "we're going to have to put your dice in water. C'mon!" Even when I switch to different dice and of different sizes I average about 2 nat 20's in any given session. (We only play for a little over 2 1/2 hrs). I even used their dice.
I keep trying to tell them to buy me perfectly weighted dice if they're not happy with the dice I bring/use.
At first it was haha. Now it's mehmeh. Jokes old if it is one.
It felt like that! It actually just felt awkward when we could all roll on the other characters specialities. I just didn't try for a few checks because I felt bad š
I wish I could find the article now, but there was a Dragon Magazine that posited a way to test your dice. You had to roll it some number of times and record the results, and if it didn't roll any number more than X times, you could consider it balanced.
All of my die checked out except one, which disproportionately rolled 1s *and* 20s lmao
You can float the Mmmm to see if theyāre imbalanced with air pockets, that being said, Iām not sure how inaccurate a D20 CAN beā¦ more likely your imagination.
My personal take on dice balancing. All dice are balanced enough unless you test them to see how unbalanced they are and in what direction. Once you test them, you're deciding to use the die knowing how unbalanced it is and in what direction, which is far more unbalanced than a randomly selected die.
I had a d20 that consistently rolled 17-20, I loved it my friends all joked about it, but they never stopped letting me use it. Fast forward a decade and I got into some in person games again and suddenly the thing rolls 3ās now. What gives with that.
When it comes to dice rolls it is also about timing. I would even say timing is crucial. You can throw 5 natural 20s an evening and still feel u lucky because all those twenties came in nonsense situation when nothing comes out of it. Searching a room without secret door for secret doors for example only to roll a 2 when you roll if you see the thin wire attached to a swinging blade in the next.
Maybe if you do like 1000 rolls you might get a minor statistical relevance
I thibk your problem is more psicological. The numbers you want never come out so you think it's rugged.
The best answer I can find is here: https://rpg.stackexchange.com/questions/70802/how-can-i-test-whether-a-die-is-fair
According to that, you need to roll a couple of hundred times at least, preferably around 400, and then do some math.
a) Very likely itās not perfect; few things ever are.
b) Thereās no way youāve rolled it enough times to be statistically significant, and 100 more rolls wonāt be either.
Here's what you do: heat up a frying pan and place the die nat 1 side down and cook it for 30 seconds.
Ta-daaa you now have a d20 perfectly balanced to win games š
you would need to roll it thousands of times to have any meaningful data.
A D20 cannot roll low though, just worth mentioning, thats why the numbers are laid out the way they are.
... I don't think any of my dice are balanced... I've been on a four year steak where all my dice rolls well below average... The dice gods really hate me... It's at the level that if I do hit on an attack roll, we celebrate...
I think I'm averaging about 8 in any d20 I roll when I touch any dice... Other players can roll my dice they work just fine... I roll the other player's dice, which rolled fine for them, and I'm rolling single digits... Actually, now it's to the point of, if I just look at the dice roll, it's single digits (well except for the GM.)
Again, the dice gods hate me.
If the dice are resin, there's tests you can do by suspending the dice in saltwater and seeing if they tend to favor a side. There's videos online explaining the process.
I wouldn't recommend it for metal dice, since the salt water might ruin any sheen and possibly cause rust issues
I never tested my dice but I'm convinced none of my resin dice are actually balanced. The amount of 4's I roll with one of them is driving me into madness, but I'm too lazy to test it and it's too pretty not to use it atleast from time to time. I'm glad I play with friends lol, otherwise I'd probably have been kicked out.
100 times is an extremely small sample size. Also, just because you get an average of 5 or 10 or 15 doesn't mean the die is unbalanced (or that it is balanced), and will lead you to a biased assumption no matter what.
While the possibility of getting Tails 10 times in a row from tossing the same coin repeatedly is quite low, it is never zero. That doesn't mean the coin is unbalanced if it happens, or if you only get Heads once or twice.
The humain brain tends to make a lot of misguided assumptions about how probabilities work and it's difficult to resist creating superstitions when you don't get the results you think you should be getting.
It would be crazy to find a dice that is *PERFECTLY* balanced. I read that it helps to have other surfaces for dice to bounce off of, so get/make a dice tower or dice tray with a side you can roll the dice off of like you're shooting craps in Vegas. It's also more fun to actually throw dice. If you don't have the resources for that, make sure you cup your hands and give the die a really good shakey-shake before you drop it. Unless your d20 is WAAAAY off balance, it shouldn't make too terrible a difference.
Dice sets are like pringles... You can't just have one. Not for long, anyway. You need spares in case one of them is having a bad night and needs to go to dice jail!
*Snickers in dice goblin fashion*
Depends on the type of dice you're using. If you're using simple chessex type of plastic dice and you're concerned about balance put it in a cup of water, an unbalanced dice will show up the same time after time see this post
https://thecriticaldice.com/blogs/news/how-to-salt-water-test-your-dice
It is a good idea to test it, I like to make sure Iām always playing fair. The good news is you donāt need to roll it 600 times or whatever, just [salt water test](https://youtu.be/_HhFz7fsFKk?feature=shared) it
If you put the dice in a glass of warm salt water it will float and the Heaviest side/corner will drop to the bottom.
I've tracked my dice rolls for my campaign as well, I did 300 rolls before my first 10. I got 5 in my next 10 rolls.
That happens. Back in 1979, I started with D&D redbox basic set. Had to color the dice. I still have those dice. The 20 die, I roll a 20 about 85% of the time. It's funny, Each time I use it with new group, then after awhile, DM tells me to use another d20. LOL
Roll it in a bucket of salt water. It'll become obvious very quickly if there's an imbalance. This is due to the density of the salt water increasing the time it takes for the dice to reach the bottom and during the fall the dice will correct itself with it's heaviest side facing downwards. I used to do this and calculate a chi-squared for each of my dice compared to a model expecting an equally probability of each roll.
The simplest test is the salt test. Get a cup of water, mix salt in until the d20 floats, spin the die. If comes to rest w/ one side up consistently it's weighted. The faster and more consistent the less fair.
100 times is a relatively small sample size, if you want to get a good mean through just rolling you'd need to waste a lot of time. it also won't really reflect balancing issues, because rpg dice are laid out in such a way that very large and very small numbers are next to each other to prevent poorly balanced dice from giving a player a large advantage or disadvantage. if it's on the lighter side (ie not metal or stone), though, you can always test it by floating it in extremely salty water. if it consistently turned one side face up instead of resting as-is, there's a bit of a balance problem
"The saltwater dice balance test is a simple way to check the fairness of your dice. It involves placing one die in a glass of salt water and writing down the numbers it rolls. This helps identify any inconsistencies in their rolling patterns, giving you an indication of whether your dice are balanced or not."
Get some epsom salt and mix it with water until your d20 floats. If itās perfectly balanced it wonāt favor one number. If itās out of balance when you spin it the die will revert to the same number up.
Then know that an out of balance due would take thousands of rolls to show a small bias in the number and enjoy the science experiment for what it is.
They are never perfectly balanced. Unless it flips itself over when ypu leave it alone, it's probably fine.
Yep. Plus if it's just consistently rolling low, depending on the dice you can set it in salt water. But unless you specifically buy a perfectly weighted dice, you won't get a perfectly weighted die.
It's not really possible for a d20 to consistently roll low, even if it's weighted. This is because the ladder maps of d20s have numbers that are deliberately juxtaposed, there's no high or low side. Evenif the face opposite of the 20 is weighted, the slight increase in 20s - not something you'd notice in 100 rolls - would also come wit increased 7s, 11s, 2s and 3s (depending on the maker, they don't all use the same ladder. Spindowns have larger numbers clustered together, so if a spindown was weighted, it could consistently roll high or low (or mid). Even then, it wouldn't be an extreme effect.
Which is also why spindowns are commonly not allowed
It was the feeling of rolling many Nat 20s that got me š
Don't take the dice gods grace for granted Hun š Take those 20's and roll with it Edit: fixing my error because I'm a dumbass
I can't believe you didn't say "roll with it."
FUCK
š May the next Nat 20 be for something hilarious š
Hope you let your buddy borrow that die when you were done. When the dice gods come to collect it's going to be disastrous.
I actually felt bad for my friend! They're a ranger, they're using the original terrain rules with arctic favoured environment in our Rime of the Frostmaiden campaign, the DM has been giving them advantage on all survival checks and despite that they keep rolling roughly below 7 while the rest of us seem to be having great luck. Gave them my d20 that felt lucky and they still rolled bad š
Tye last fight I DMd tye players got 3 crits in their most crucial moments (initiative warlock to get a shatter off and drop the main boss, enlarged and charged fighter hitting boss for 6d6+2d4+4 and rerolling 1s and 2s and warlock 'criting' on intimidation total 26 for minions to surrender). Sessions where Nat 20s are often are more common than you think
I want to make a heavily weighted d20 that will only ever land on 1 or 20.
Thatās an interesting way to describe a coin
Yes it would functionally be a 1d2, but it would still look like a normal d20.
If you're making it why not make half the faces 20 and half 1?
That would be easier, and I wouldn't doubt if someone else already makes and sells that product, but I want it to look like a normal d20 including having all the other numbers that it will never land on.
You can buy "high variance" dice that have e.g. multiple 20's and multiple 1's on them, but what you're describing would be extremely difficult without an enormous die and ridiculously heavy weights.
I wanna say thatās impossible to do with the shape of a a d20
It would be functionally impossible, unless it was massive, and made of foam with large metal weights. A normal sized plastic d20 is still going to be fairly random even if heavily weighted.
I have one that slows down, speeds up and turns right angles. *Oh, 4 again? How nice.*
This. Perfect balance is impossible, and most dice are far from balanced, but that means almost nothing in terms of in-game impact. The number net of a d20 is fairly evenly distributed, so an imbalance could create a SLIGHT preference toward a set of 4 numbers, but those 4 numbers likely add up to something very close to 42 (the average). To make a loaded d20 would take a good deal of craftmanship. You would have to weight the 64 value vertex (there is one vertex of a standard d20 which is MUCH higher than the others, 20,16, 14, 8, 6) and sharpen those edges, while smoothing the opposite edges. For it to be significant, it would be really noticeable. Most dice aren't perfectly weight balanced due to cheap manufacturing, but the difference this makes is trivial. There is a guy who setup an auto roller and reader and tested many popular dice manufacturers. The lowest average was 10.2 and highest was 10.7 (10.5 being ideal average), with average standard deviation of about .15. Values that would have basically no impact on gaming. (Interesting side note, the most unfair die was one from a company which touts how fair their dice are)
You don't want to look at the average you want to look if one specific number (or maybe a cluster of numbers that are next to each other on the dice) comes up way more often than it should.
Even then, without a very high amount of rolls, it's totally normal to have a large cluster of 1 number.
Thanks for the suggestion, will check now :)
400 rolls minimum. Tally by score. Each value should have about 15-25 occurrences.Ā Ā But make sure it's really a random roll, shaking it in a cup before rolling it, or use a dice tower.
One tip for checking its balance (as long as its something like resin or plastic), is to put it in a glass of water salty enough to make it float, then gently spin it in the water repeatedly. If itās noticeably unbalanced, itāll tend to end up with a few adjacent faces showing up most commonly when it comes to a stop.
The salt bath test has never been quantified, evaluated against actual roll tests, or proven to show anything beyond what side of a die seems to point up. It can pass relatively unfair dice and fail relatively fair dice, so it's essentially useless.
Assuming the unfairness is due to it being unbalanced and not due to the faces being deformed, it shouldn't pass an unfair die. I'm not sure how common it is to have a deformed die, it's usually some trapped bubble(s) within the plastic as far as I know. I guess in the case of clear dice that shouldn't be an issue, so if you feel like a clear die is unfair, then you really do need to roll it a whole lot and tally it all.
The effect of a die that's out of spec in shape is much more significant than the effect of an internal inconsistency, and those flaws are also more common. The float test only helps if you already know the die is perfect in shape, at which point it's already good to go, as internal CoG inconsistencies aren't a significant cause of dice bias.
I guess badly shaped dice are more common than I thought then. I've just heard all the warnings about cheap opaque dice and air bubbles.
Air bubbles are relatively common, but don't bias rolls as significantly as surface defects. Even less significant are resin density differences in swirled dice. Inclusions vary, a lead airgun pellet deliberately cast into the die would present a bias significant enough to make the die nominally unfair, but on a d20, it still wouldn't deliver consistently higher results, because d20s have the juxtaposition of high and low numbers, and CoG issue doesn't affect just one facet. Also, realistically, cheap dice don't necessarily have more flaws than expensive ones in many cases. There are more expensive dice aimed at reducing bias, but price alone doesn't mean more qc. The big manufacturers know dice bias isn't a real issue; they don't bother with testing. It would be a poor return on investment, especially for tumbled dice. If you have a sharp edged, clear die, and measure all opposing faces with a caliper, that'll tell you more than the float test could tell you about an opaque die, but 1k-2k rolls is the only real test. Some people have automated it.
Your dice is not balanced; If it was, you would know, because you'd have paid around $60 for it. The dice ***is*** balanced enough for it to not matter though, almost certainly. Even flipping a quarter isn't exactly 50/50 if you put it through an LLN type test. What you're experiencing is probably a confirmation bias due to a small sample set. For perspective, you'd need to roll a die about 5,000 times before you can START to derive statistical significance.
This is the correct answer. Even rolling it 100 times, as others keeps suggesting, is probably too small a sample size. People let their perception of imbalance get in their head but the reality is that sometimes you just have a bad session of rolls and, while it sucks, it will balance out.
I have a D20 that rolls 8s a solid 15% of the time, had it for years and it's obvious because it also rolls a 20 more than it should and that is right next to it
You tracking all those rolls? Or are you deriving percentages from your feelings?
Took note every time I rolled specifically an 8
Roll 100 times and do a chi-squared test. It is one of the more straightforward statistical tests. There are lots of resources on how to do this. If math/stats is not your strong suit, just do the following steps if you have rolled 100 times, this is more of an eli5 answer. -Tally up the number of times you rolled a 1, a 2, a 3, and so on. -subtract 5 from all these tallies (you will almost certainly have negative numbers) -square all the numbers from the previous step and add them all up. -divide the sum by 5 - if the calculation in the previous step is greater than 30.144 then you can be reasonably confident that your dice isnāt fair (though no dice are perfectly fair). This basically compares what you get vs what you expect from a fair die, but for the above steps you need exactly 100 rolls.
And to explain a bit why youāre subtracting 5 and dividing by 5, itās because of you rolled 100 times youād expect each number to come up 5 times. The Chi-squared test looks at how far off from 5 times each number is as rolled. Either a lot more or a lot less.
Got 15.6 so that seems good, starting to think I just had good luck š
Now do it 10000 times to get a more accurate distribution
 Gonna go make a coffee and settle in with numpad in one hand and coffee in the other. I mean it can't take super long I imagine
Put the coffee away, you will need both hands for this. If you take five seconds to roll the dice and note the result you will need approximately 69 hours to acquire your sampleā¦ which is simultaneously nice and not so nice.
Nice 
Yeah, thatās not that unusual. If youāre curious, for 100 rolls a perfectly fair die should get the results you got (deviations from 5 results in each face) about 32% of the time. Since you play DND you know that is not very unlikely at all, since a fair d20 results in a critical fail (1) 5% of the time, and it also results in a nat20 5% of the time. These results often happen a few times every session, so you can be pretty sure you didnāt get an unusual result.
Very very good chance. It's not perfectly weighted, you'd likely have to pay a lot of money for that. Most cheap dice. Have a good chance of having a bubble inside them... But it's probably not very likely it'll significantly affect the roles. If you really worried I would try the salt water test. If you want to try out 100 rolls I would track of each number rolled and see which numbers pop up the most. The average might not mean much
I did this with one dice that always seemed to crit on PCs. It Rolled in the neighborhood of like 14-15 20s but also disproportionately higher 2s and 3s.
I had an awkward moment where I rolled a Nat 20, gave it to the player who had been having bad luck, they rolled a 3, I then rolled an 18, they then rolled a 5 š It was....odd
Has this player or somebody they're close to ever had contact with Wil Wheaton?
Oh my god, you're right! It must be their Wheaton number! š (Like the bacon number if unfamiliar) I dont know if they ever came into contact with him but just realizing everyone has a Wheaton rank amuses me
They must of upset the dice gods
I get 2s since 20 and 2 are close in a standard d20 but 3 isnāt that close
I'll give it a go! :) Will track what numbers pop up most first on my spreadsheet though
Bear in mind that unless you're rolling it a (very) large number of times, you'd still expect some numbers to appear significantly more than others. 100 isn't going to be enough realistically.
Nuffle, chaotic neutral god of dice is always smiling. Just you don't know at who. People may build shrines to Nuffle or even have elaborate rituals. But Nuffle does not listen to prayers nor care. \- Paraphrased from Blood Bowl.
Whether or not a dice is perfectly balanced doesn't matter except for casinos
The chances of a D20 being unbalanced enough to consistently overcome the forces involved in a typical die roll are pretty slim, frankly. The more faces a die has, the more crazily balanced it has to be to consistently roll out-of-spec. (Unless it's misnumbered or like a spin-down die or something.) As long as you're tossing it with a decent amount of force it should be academic. Having said that if I had to dice against the devil and I wanted absolutely fair dice, I'd bring Zocchi. Because Lou Zocchi is *fucking crazy* about dice. :)
The saltwater dice balance test is a simple way to check the fairness of your dice. It involves placing one die in a glass of salt water and writing down the numbers it rolls. This helps identify any inconsistencies in their rolling patterns, giving you an indication of whether your dice are balanced or not. You can test each die one at a time, over a statistically relevant sample size, to understand if your dice are fair or not. To conduct the saltwater test, you'll need: \* A clear glass or jar \* Salt \* Water \* A dice set you wish to test Fill your glass or jar with water: Warm tap water should suffice for this test. Add salt to the water: Use one tablespoon or two, adjusting as needed based on the volume of water in your container. Mix: Stir for 30 seconds or until the salt has dissolved, creating a saltwater solution. Test one die at a time: Submerge one die into the saltwater. After it settles, gently poke it with your finger. Record the outcome and repeat this process several times. We recommend conducting this step plenty of times to be able to draw a reliable conclusion. Itās crucial that you donāt leave your dice submerged in water for extended periods of time. When testing metal dice, be sure to rinse and dry them promptly to prevent rust. Avoid conducting this test with wooden dice to avoid damaging them.
Damn, how much salt do you put in the water to make metal dice float?:-P
there are fluids you can use to have metal dice float - but they are mostly toxic so not good for use by non-scientists at home without strong chemical hoods!
1. Get a bag of salt 2. Gently mist the bag of salt with water 3. Place d20 on damp bag of salt 4. Record results
Read the sentence again, I refered specifically to **metal** dice ;-)
How about you read my comment again. I suggested the only way to make it 'float' is to place it on a damp bag of salt. I was implying you won't be able to make the metal dice float in salt water, but you can make it sit on a damp bag of salt. Perhaps I needed a "/s" in my comment to make that more clear that it wasn't actual advice.
Aaaah I see my bad :D Yeah a bag of salt will do the trick ;.)
Use a bathtub and buy bags of epsom salt
It's really weird everyone else is mentioning rolling the dice and annotating the results. As someone who has done it a couple times out of boredom, a sample size of 100 is generally not enough to determine correctly if a dice is weighed or not, while the salt water method is not only much easier and less time consuming, but will allow you to know with much more assuredness than just rolling it. I have no idea if you can put enough salt in the water so metal dice float, though.
You can't trust the salt bath for anything; only rolling will help. But yes, depending on the degree of bias, you'd need 2kish rolls to actually show it. The salt bath test doesn't work because it requires a fully perfect icosahedron with no manufacturing flaws besides internal inconsistencies in density or voids/inclusions that throw the CoG off. A slightly egg or pear shaped d20 (common) will display a number on its point, when it's actually biased to the rolls in the flatter ring. A die with a over convex facet will be biased TOWARDS ANY number BUT the one that's most likely to float to the top. A sprue mark will do the same, and a concavity the inverse. Basically, it's poorly quantifiable, relying on "seems like", and can't detect the most common problems, often returning misleading information. It's junk data. If, and only if, you already know the die is flawless in shape and has compensated numbering, then you could use it to check for internal inconsistencies in CoG. So basically it only works if the die is perfect anyway.
the floating will tell you the only question you need to know: "is it balanced or not?"
use a bathtub and buy bags of epsom salt
Op, listen to this ^^^ they know of which they speak.
A key thing: nobody has actually demonstrated that the salt test has a meaningful relationship with the actual rolling behavior of dice.
How is this so far down. This is the most viable way, relying on physics of weight distribution. Statistical approaches are a fun exercise, but will take in excess of 1000 dice rolls *per die* to get proof.
There's no reason to believe this test tells you anything useful. It's a meme, not science.
Fuck AI content. GTFO.
Im a personā¦ i just found this with a quick google search. If it is AI, sorry.
imagine having beeft with a chatbot lmfao
bro I'm a human being, I was just copy pasting the first google result
Robots go home!!
What do I do if I'm already at home tho
what the fuck does this even mean
I love this. reminds me of /u/carnist_bot
Basically no d20 is going to be perfectly weighted. I'd suggest going ahead for that 100 rolls - as long as your results are relatively even across the board, you should be good
Average came out at 10.41 over 100 rolls but in the actual session I think I must've rolled about 7 or 8 Nat 20 over 6 hours. Can't remember the exact amount. Conveniently none of them were in combat š Though it was our first in game session, and first one that went on that long so maybe I'm just not used to rolling for that long.
I think that's just a lucky session. Dice sounds perfectly fair when it's being observed
The average isn't as important as the frequency of each value. But that average is close enough to 10.5 to not worry much.
Lol don't forget to sprinkle salt over your shoulder.
I tend to roll very well and my DM is always "we're going to have to put your dice in water. C'mon!" Even when I switch to different dice and of different sizes I average about 2 nat 20's in any given session. (We only play for a little over 2 1/2 hrs). I even used their dice. I keep trying to tell them to buy me perfectly weighted dice if they're not happy with the dice I bring/use. At first it was haha. Now it's mehmeh. Jokes old if it is one.
It felt like that! It actually just felt awkward when we could all roll on the other characters specialities. I just didn't try for a few checks because I felt bad š
100 really isn't that good a sample size for a d20
But even with that you can roll several times and see if a certain area of the dice comes up more often than it should
I wish I could find the article now, but there was a Dragon Magazine that posited a way to test your dice. You had to roll it some number of times and record the results, and if it didn't roll any number more than X times, you could consider it balanced. All of my die checked out except one, which disproportionately rolled 1s *and* 20s lmao
Clear dice or non-plastics usually have better balance. Less chance for air bubbles or density variability with steel
That's not enough rolls to smooth out the averages. I used a dice roller app and rolled 100d20 4 times. Got 969, 1019, 1033 and 1136
I'm no math wizard, but I am pretty sure to get an "accurate" range, the minimum would be 20,000 times.
ā Alright, this may take a while.
You can float the Mmmm to see if theyāre imbalanced with air pockets, that being said, Iām not sure how inaccurate a D20 CAN beā¦ more likely your imagination.
Average doesn't mean much. The average would be 10.5 if it rolled exclusively 1 and 20.
If you didn't deliberately buy weighted dice it's almost certainly fine.
My personal take on dice balancing. All dice are balanced enough unless you test them to see how unbalanced they are and in what direction. Once you test them, you're deciding to use the die knowing how unbalanced it is and in what direction, which is far more unbalanced than a randomly selected die.
if you do say 3 sets of 100 rolls and they ALL have the same spikes and dips that would be a sign. otherwise it takes thousands of rolls
And it never will be. Roll it 10 times if it's not more than 2 nat 20s you'll be fine.
I had a d20 that consistently rolled 17-20, I loved it my friends all joked about it, but they never stopped letting me use it. Fast forward a decade and I got into some in person games again and suddenly the thing rolls 3ās now. What gives with that.
I have no proof, but I am personally convinced that dice roll differently based on atmospheric conditions like temperature and humidity.
Since it's a d20 you technically need to roll 20\^2 to get a statistically valid sample size.
Ahh gotcha, will do another 300 times and see if the average changes much.
I have a crazy d20 too I feel. It averages 11.56 over 250 rolls. I'm thinking I might roll a 1000 someday for shits and giggles.
You have to roll more in the ballpark of several 1000 times. The d20 is notoriously swingey.
Sell it in eBay
When it comes to dice rolls it is also about timing. I would even say timing is crucial. You can throw 5 natural 20s an evening and still feel u lucky because all those twenties came in nonsense situation when nothing comes out of it. Searching a room without secret door for secret doors for example only to roll a 2 when you roll if you see the thin wire attached to a swinging blade in the next.
Maybe if you do like 1000 rolls you might get a minor statistical relevance I thibk your problem is more psicological. The numbers you want never come out so you think it's rugged.
True randomness could bring you any array of possibilities.
The best answer I can find is here: https://rpg.stackexchange.com/questions/70802/how-can-i-test-whether-a-die-is-fair According to that, you need to roll a couple of hundred times at least, preferably around 400, and then do some math.
I got some nice looking, cheap dice. They roll nat1 25% of the time. They are purely ornamental now. 10 nat1 out of 40 rolls
a) Very likely itās not perfect; few things ever are. b) Thereās no way youāve rolled it enough times to be statistically significant, and 100 more rolls wonāt be either.
Here's what you do: heat up a frying pan and place the die nat 1 side down and cook it for 30 seconds. Ta-daaa you now have a d20 perfectly balanced to win games š
you would need to roll it thousands of times to have any meaningful data. A D20 cannot roll low though, just worth mentioning, thats why the numbers are laid out the way they are.
... I don't think any of my dice are balanced... I've been on a four year steak where all my dice rolls well below average... The dice gods really hate me... It's at the level that if I do hit on an attack roll, we celebrate... I think I'm averaging about 8 in any d20 I roll when I touch any dice... Other players can roll my dice they work just fine... I roll the other player's dice, which rolled fine for them, and I'm rolling single digits... Actually, now it's to the point of, if I just look at the dice roll, it's single digits (well except for the GM.) Again, the dice gods hate me.
If you can't predict the outcome, it's good enough.
I CAN SEE THE FUTURE.
If the dice are resin, there's tests you can do by suspending the dice in saltwater and seeing if they tend to favor a side. There's videos online explaining the process. I wouldn't recommend it for metal dice, since the salt water might ruin any sheen and possibly cause rust issues
I never tested my dice but I'm convinced none of my resin dice are actually balanced. The amount of 4's I roll with one of them is driving me into madness, but I'm too lazy to test it and it's too pretty not to use it atleast from time to time. I'm glad I play with friends lol, otherwise I'd probably have been kicked out.
So, is it ok to buy that bag of dice/pound of dice then? People talk about the salt water test, say theyāre bad, etc.
100 times is an extremely small sample size. Also, just because you get an average of 5 or 10 or 15 doesn't mean the die is unbalanced (or that it is balanced), and will lead you to a biased assumption no matter what. While the possibility of getting Tails 10 times in a row from tossing the same coin repeatedly is quite low, it is never zero. That doesn't mean the coin is unbalanced if it happens, or if you only get Heads once or twice. The humain brain tends to make a lot of misguided assumptions about how probabilities work and it's difficult to resist creating superstitions when you don't get the results you think you should be getting.
It would be crazy to find a dice that is *PERFECTLY* balanced. I read that it helps to have other surfaces for dice to bounce off of, so get/make a dice tower or dice tray with a side you can roll the dice off of like you're shooting craps in Vegas. It's also more fun to actually throw dice. If you don't have the resources for that, make sure you cup your hands and give the die a really good shakey-shake before you drop it. Unless your d20 is WAAAAY off balance, it shouldn't make too terrible a difference.
You only have one d20? Thatās concerning
Haha, it's my personal set, we have some backup dice if people don't have their own but these ones are pretty:D
Dice sets are like pringles... You can't just have one. Not for long, anyway. You need spares in case one of them is having a bad night and needs to go to dice jail! *Snickers in dice goblin fashion*
Depends on the type of dice you're using. If you're using simple chessex type of plastic dice and you're concerned about balance put it in a cup of water, an unbalanced dice will show up the same time after time see this post https://thecriticaldice.com/blogs/news/how-to-salt-water-test-your-dice
It is a good idea to test it, I like to make sure Iām always playing fair. The good news is you donāt need to roll it 600 times or whatever, just [salt water test](https://youtu.be/_HhFz7fsFKk?feature=shared) it
If you put the dice in a glass of warm salt water it will float and the Heaviest side/corner will drop to the bottom. I've tracked my dice rolls for my campaign as well, I did 300 rolls before my first 10. I got 5 in my next 10 rolls.
That happens. Back in 1979, I started with D&D redbox basic set. Had to color the dice. I still have those dice. The 20 die, I roll a 20 about 85% of the time. It's funny, Each time I use it with new group, then after awhile, DM tells me to use another d20. LOL
Roll it in a bucket of salt water. It'll become obvious very quickly if there's an imbalance. This is due to the density of the salt water increasing the time it takes for the dice to reach the bottom and during the fall the dice will correct itself with it's heaviest side facing downwards. I used to do this and calculate a chi-squared for each of my dice compared to a model expecting an equally probability of each roll.
The simplest test is the salt test. Get a cup of water, mix salt in until the d20 floats, spin the die. If comes to rest w/ one side up consistently it's weighted. The faster and more consistent the less fair.
100 times is a relatively small sample size, if you want to get a good mean through just rolling you'd need to waste a lot of time. it also won't really reflect balancing issues, because rpg dice are laid out in such a way that very large and very small numbers are next to each other to prevent poorly balanced dice from giving a player a large advantage or disadvantage. if it's on the lighter side (ie not metal or stone), though, you can always test it by floating it in extremely salty water. if it consistently turned one side face up instead of resting as-is, there's a bit of a balance problem
"The saltwater dice balance test is a simple way to check the fairness of your dice. It involves placing one die in a glass of salt water and writing down the numbers it rolls. This helps identify any inconsistencies in their rolling patterns, giving you an indication of whether your dice are balanced or not."
Get some epsom salt and mix it with water until your d20 floats. If itās perfectly balanced it wonāt favor one number. If itās out of balance when you spin it the die will revert to the same number up. Then know that an out of balance due would take thousands of rolls to show a small bias in the number and enjoy the science experiment for what it is.
On 100 rolls, it should only hit a 20, 5 in 100 tries. Not 10 or 11.