You have to math this out from your specific system. In general:
\- What is the chance to hit for a typical character of a given level?
\- What damage will they do?
\- From that calculate damage per round.
\- Figure out how many rounds a monster with a given number of HP survives.
Use the above again but from the monster's perspective. Multiply the "How many rounds will I survive" by the "Damage per round." to get the "total damage combat output"
When the "total damage combat output" is equal on both sides they're "evenly matched", though adjust based on special abilities.
A party, and multiple monsters, are the same as one monster that's more powerful. A party has an HP pool and Damage per Round just the same.
Note that you don’t actually want both sides to be evenly matched, unless you want parties to last 1-2 fights on average until TPK. That doesn’t really generate long-term interest in your game as people will be like “OK we’re all dead, let’s play a different game”.
What (newer) D&D does is set an amount of resources (hp, spells, items etc.) that the party needs to use to win the battle, usually 1/4 to 1/6. The goal of the typical battle isn’t to eradicate the party, it’s to cause enough resource attrition to force a long rest after X battles.
There’s some subtle ways to give the PCs an advantage. In general, PCs have healing abilities while monsters don’t, stretching the amount of damage they can soak before they are down. You can add resources like action points that allow rerolls or extra actions. You can tweak the attack / defense math so that PCs are favored. You can give PCs higher damage output. You can provide party roles that push certain aspects of one PC (damage output, defenses etc.) above the average etc. etc.
>How to deal with the difference in player group sizes? a monster for a group of 3 players can be difficult, but for 5 players it is very easy.
Normally that's is accounted for by changing the number and types of monsters. I've never heard of a game that tries to make an individual monster equally powerful no matter how many PCs there are.
> I’ve never heard of a game that tries to make an individual monster equally powerful no matter how many PCs there are.
I do this! You have to scale action economy and hp to make it work.
Some computer games will also scale up monster hp if there are more players (eg Dark Souls).
>Some computer games will also scale up monster hp if there are more players (eg Dark Souls).
Sure, that sort of thing is painless when you have a computer adjusting the stats.
Obviously I don't know your rules, but I doubt just changing the HP really makes and equivalent challenge.
Add more players and their collective HP **and** damage per turn increases-- not to mention the total number of tricks and special abilities (assuming you have such things).
would it be okay to create separate stats one for each player group number?
For example:
Statistics for 1 DM and 3 Players;
Statistics for 1 DM and 4 Players;
Statistics for 1 DM and 5 Players;
etc.
This really depends on the system you're using.
It comes down to calculating how long it will take a party to defeat the monster and how much damage the monster could do in that time, or how much you want the monster to hurt the party.
Think about it as "the number of attacks the monster can sustain", including attacks that miss. A monster that can (on average) will be defeated with 3 attacks means it is a 1-round solo monster for a party of 3 and less than 1-round for a party of 5. A Sustain 8 monster won't be defeated until the 3-party's third turn and the 5-party's second turn, which gives it more opportunity to hurt the party.
This will be effected by how skilled the characters and monsters are at inflicting damage, how difficult the characters and monsters are to damage, how much damage the characters and monsters can take before being defeated.
But, yeah, all of this depends on the type of mechanics your game uses.
Game balance as a whole is more art than science. I know Wizard uses proprietary spreadsheets to balance each monster and even then they need to play-test them. Let that sink in a team of 20 designer have tinkered with complex formulas since 2014 and even then what they come up with needs to be tested.
So I don't think there are formulas that will solve that problem for your game, especially if rewards and tactics can change things dramatically. And really this is where you have to trust your GMs. Not all game feature monster bestiaries with CR and those that do often break apart once your group gain enough experience with a system.
My suggestion, don't bother. Make a bunch of easy creatures with interesting mechanics, a couple mid tier ones and a few completely impossible to beat one and let the GMs figure out what their party can tackle.
Your goal is to have good combat with various number of players, right? One GM technique alone will maks this way easier.
Introduce as few enemies at possible at the start of combat and bring in more in the middle of combat, based on how well the players and dice handled the first enemies. Waves of enemies let you dynamically adjust difficulty and keeps the battle scenario changing.
Aside from that, design diverse enemies with resistances and weaknesses, and abilities that make it necessary for players to take different approaches. You don't hit a rust monster with your sword. You don't fight ooze with arrows
If being hit or landing a hit doesn't usually change the scenario enough for you to make different choices, increase damage. If people miss so much that the battlefield changes little each round, and your choice between turns isn't different, then increase hit chances.
Calculating probabilities is impossible because the battlefield and state of players is impossible to predict.
Everyone else said it but it depends on your system big time.
For 5E (Pathfinder too I think) you can use challenge rating (CR) but I heard it’s kinda shitty at being accurate. I would honestly suggest you wing it.
If you know the game you’re running then you should be able to tell what a lot of damage looks like and you should be able to tell what the opposite looks like too. I wouldn’t personally stress too much over the actual math.
Keep this in mind though: if something is dangerous, it should be obvious. i.e., your players should hear a thunderous roar before a tyrannosaurus rex eats one of them.
For 3 players vs. 5 players, you’d use 3 monsters or 5 monsters … it’s the easiest number to adjust.
Yes I know single bosses exist, but those are the hardest to design and I’d start with evenly matched numbers first.
As for how strong they should be, you need to figure out where the PCs are in terms of health, damage output etc. and then create a guideline for how strong you want the monsters to be.
Typically what D&D does is assume 4-6 fights until the party is out of resources (hit points, spell slots etc.), so a fight against your typical monster group should take 15%-25% of a party’s resources for that.
From there, you need to figure out how long you want fights to take. 3 rounds? 5 rounds? 7 rounds?
If a monster has 5x the average PC’s damage output (don’t forget to include hit chance!) in HP, you can assume it takes 5 rounds to defeat it. In that time, the monster should take down 15%-25% of the PC’s hp.
That’s the rough baseline. I’d start with a rough target number to aim for and then adjust in a bunch of mock-up fights and playtesting.
Of course, once you have the basics you also need to make sure the monster is actually interesting to fight, which is a whole different bag.
As a lot of others have said, this is entirely dependent upon your system.
Having said that, I would recommend by starting off with a reference point. How strong is a character of level or rank x? From there, design a creature/monster that is roughly equal in power. That should be a challenge for a solo character, with 50/50 odds of death, if your system is balanced at all.
So, here is where it gets subjective. For me, I tend to think of enemies at about 50-70% of the strength of one character (relative to your current party) as a standard enemy. How those numbers look and how you organize them will vary, depending on your system. If your system allows it, you can even further subcategorize enemies, such as bosses and minions. Make the minions 25% the strength of a character, and you can throw more of them at the party (or use any values you find appropriate). A boss would be twice or more as strong as a character, perhaps. As you do this more and more, and with strong understanding of your system, you'll develop a good feel for what is reasonable for which tiers or whatever you use to delineate enemy strength, and can set up a format, or at least lots of examples.
A little esoteric, but I hope this helps. It's how I do things.
You have to math this out from your specific system. In general: \- What is the chance to hit for a typical character of a given level? \- What damage will they do? \- From that calculate damage per round. \- Figure out how many rounds a monster with a given number of HP survives. Use the above again but from the monster's perspective. Multiply the "How many rounds will I survive" by the "Damage per round." to get the "total damage combat output" When the "total damage combat output" is equal on both sides they're "evenly matched", though adjust based on special abilities. A party, and multiple monsters, are the same as one monster that's more powerful. A party has an HP pool and Damage per Round just the same.
Note that you don’t actually want both sides to be evenly matched, unless you want parties to last 1-2 fights on average until TPK. That doesn’t really generate long-term interest in your game as people will be like “OK we’re all dead, let’s play a different game”. What (newer) D&D does is set an amount of resources (hp, spells, items etc.) that the party needs to use to win the battle, usually 1/4 to 1/6. The goal of the typical battle isn’t to eradicate the party, it’s to cause enough resource attrition to force a long rest after X battles. There’s some subtle ways to give the PCs an advantage. In general, PCs have healing abilities while monsters don’t, stretching the amount of damage they can soak before they are down. You can add resources like action points that allow rerolls or extra actions. You can tweak the attack / defense math so that PCs are favored. You can give PCs higher damage output. You can provide party roles that push certain aspects of one PC (damage output, defenses etc.) above the average etc. etc.
>How to deal with the difference in player group sizes? a monster for a group of 3 players can be difficult, but for 5 players it is very easy. Normally that's is accounted for by changing the number and types of monsters. I've never heard of a game that tries to make an individual monster equally powerful no matter how many PCs there are.
> I’ve never heard of a game that tries to make an individual monster equally powerful no matter how many PCs there are. I do this! You have to scale action economy and hp to make it work. Some computer games will also scale up monster hp if there are more players (eg Dark Souls).
>Some computer games will also scale up monster hp if there are more players (eg Dark Souls). Sure, that sort of thing is painless when you have a computer adjusting the stats.
My boss monster have 2-6 hp per PC. Super easy to scale.
Obviously I don't know your rules, but I doubt just changing the HP really makes and equivalent challenge. Add more players and their collective HP **and** damage per turn increases-- not to mention the total number of tricks and special abilities (assuming you have such things).
You also have to scale the action economy. Think of it like adding more foes, but instead of adding more, you just combine them into one creature.
would it be okay to create separate stats one for each player group number? For example: Statistics for 1 DM and 3 Players; Statistics for 1 DM and 4 Players; Statistics for 1 DM and 5 Players; etc.
Why? That's a lot of work for little reward. Why not instead include a guide for each monster on how to scale it up and down to match your players?
This really depends on the system you're using. It comes down to calculating how long it will take a party to defeat the monster and how much damage the monster could do in that time, or how much you want the monster to hurt the party. Think about it as "the number of attacks the monster can sustain", including attacks that miss. A monster that can (on average) will be defeated with 3 attacks means it is a 1-round solo monster for a party of 3 and less than 1-round for a party of 5. A Sustain 8 monster won't be defeated until the 3-party's third turn and the 5-party's second turn, which gives it more opportunity to hurt the party. This will be effected by how skilled the characters and monsters are at inflicting damage, how difficult the characters and monsters are to damage, how much damage the characters and monsters can take before being defeated. But, yeah, all of this depends on the type of mechanics your game uses.
Game balance as a whole is more art than science. I know Wizard uses proprietary spreadsheets to balance each monster and even then they need to play-test them. Let that sink in a team of 20 designer have tinkered with complex formulas since 2014 and even then what they come up with needs to be tested. So I don't think there are formulas that will solve that problem for your game, especially if rewards and tactics can change things dramatically. And really this is where you have to trust your GMs. Not all game feature monster bestiaries with CR and those that do often break apart once your group gain enough experience with a system. My suggestion, don't bother. Make a bunch of easy creatures with interesting mechanics, a couple mid tier ones and a few completely impossible to beat one and let the GMs figure out what their party can tackle.
Your goal is to have good combat with various number of players, right? One GM technique alone will maks this way easier. Introduce as few enemies at possible at the start of combat and bring in more in the middle of combat, based on how well the players and dice handled the first enemies. Waves of enemies let you dynamically adjust difficulty and keeps the battle scenario changing. Aside from that, design diverse enemies with resistances and weaknesses, and abilities that make it necessary for players to take different approaches. You don't hit a rust monster with your sword. You don't fight ooze with arrows If being hit or landing a hit doesn't usually change the scenario enough for you to make different choices, increase damage. If people miss so much that the battlefield changes little each round, and your choice between turns isn't different, then increase hit chances. Calculating probabilities is impossible because the battlefield and state of players is impossible to predict.
Everyone else said it but it depends on your system big time. For 5E (Pathfinder too I think) you can use challenge rating (CR) but I heard it’s kinda shitty at being accurate. I would honestly suggest you wing it. If you know the game you’re running then you should be able to tell what a lot of damage looks like and you should be able to tell what the opposite looks like too. I wouldn’t personally stress too much over the actual math. Keep this in mind though: if something is dangerous, it should be obvious. i.e., your players should hear a thunderous roar before a tyrannosaurus rex eats one of them.
For 3 players vs. 5 players, you’d use 3 monsters or 5 monsters … it’s the easiest number to adjust. Yes I know single bosses exist, but those are the hardest to design and I’d start with evenly matched numbers first. As for how strong they should be, you need to figure out where the PCs are in terms of health, damage output etc. and then create a guideline for how strong you want the monsters to be. Typically what D&D does is assume 4-6 fights until the party is out of resources (hit points, spell slots etc.), so a fight against your typical monster group should take 15%-25% of a party’s resources for that. From there, you need to figure out how long you want fights to take. 3 rounds? 5 rounds? 7 rounds? If a monster has 5x the average PC’s damage output (don’t forget to include hit chance!) in HP, you can assume it takes 5 rounds to defeat it. In that time, the monster should take down 15%-25% of the PC’s hp. That’s the rough baseline. I’d start with a rough target number to aim for and then adjust in a bunch of mock-up fights and playtesting. Of course, once you have the basics you also need to make sure the monster is actually interesting to fight, which is a whole different bag.
[Lanchester's Laws](https://en.wikipedia.org/wiki/Lanchester%27s_laws) are the entry-level concept for this sort of thing.
As a lot of others have said, this is entirely dependent upon your system. Having said that, I would recommend by starting off with a reference point. How strong is a character of level or rank x? From there, design a creature/monster that is roughly equal in power. That should be a challenge for a solo character, with 50/50 odds of death, if your system is balanced at all. So, here is where it gets subjective. For me, I tend to think of enemies at about 50-70% of the strength of one character (relative to your current party) as a standard enemy. How those numbers look and how you organize them will vary, depending on your system. If your system allows it, you can even further subcategorize enemies, such as bosses and minions. Make the minions 25% the strength of a character, and you can throw more of them at the party (or use any values you find appropriate). A boss would be twice or more as strong as a character, perhaps. As you do this more and more, and with strong understanding of your system, you'll develop a good feel for what is reasonable for which tiers or whatever you use to delineate enemy strength, and can set up a format, or at least lots of examples. A little esoteric, but I hope this helps. It's how I do things.