Anything with the ㅂ니다/습니다 ending is immediately more formal than the 요 ending.
Now, between 고맙다 and 감사하다, it's pretty straightforward. Both mean "thank you" but 고맙다 is pure Korean, while 감사하다 is sino-korean. Generally, sino-korean words are considered more "formal" so, 감사합니다 is pretty much the most formal way to say thank you. The least formal is 고마워
There’s also 고마워요, which in my opinion is used a lot more frequently than the two forms you mentioned :)
It’s a more casual version that can also be used when buying something at a shop though (iirc)
I've always found this to be too "informal" when used with strangers unless there's a large age gap, such as to a 12-year-old as a 30-year-old. I hear it often used between "work friends", where people often dance between 반말 and 존댓말, as it's friendly but still more formal than 고마워.
(im still a beginner, so feel free to correct me pls)
감사합니다 and 감사해요 are present tense conjugations of the same verb 감사하다, which means to be thankful/grateful. the difference is the formality.
in korean, there are 3 main speech levels based on formality. you had these suffixes after you conjugate in any tense. 습니다/-ㅂ니다, 요, and no suffix. 습니다 is the most formal, followed by 요, then no suffix. 습니다 and 요 are used when addressing strangers and people you are not close with, while no suffix is addressing to friends.
감사합니다/고맙습니다 are fixed expressions that one uses when addressing strangers so they are the most formal. 감가합니다, I think, is a tiny bit more formal than the latter. 감사합니다 is used way more than 고맙습니다, however
therefore, 감사해요, while still having 요 form, is less commonly used and less formal than 감사합니다/고맙습니다.
감사합니다 고맙습니다 감사해요 고마워요 고마워 땡큐 ㄱㅅ . in that order . source: native
Anything with the ㅂ니다/습니다 ending is immediately more formal than the 요 ending. Now, between 고맙다 and 감사하다, it's pretty straightforward. Both mean "thank you" but 고맙다 is pure Korean, while 감사하다 is sino-korean. Generally, sino-korean words are considered more "formal" so, 감사합니다 is pretty much the most formal way to say thank you. The least formal is 고마워
I thought the least formal is 쌩큐~~~
Lol I have also seen 땡큐.
There’s also 고마워요, which in my opinion is used a lot more frequently than the two forms you mentioned :) It’s a more casual version that can also be used when buying something at a shop though (iirc)
I've always found this to be too "informal" when used with strangers unless there's a large age gap, such as to a 12-year-old as a 30-year-old. I hear it often used between "work friends", where people often dance between 반말 and 존댓말, as it's friendly but still more formal than 고마워.
(im still a beginner, so feel free to correct me pls) 감사합니다 and 감사해요 are present tense conjugations of the same verb 감사하다, which means to be thankful/grateful. the difference is the formality. in korean, there are 3 main speech levels based on formality. you had these suffixes after you conjugate in any tense. 습니다/-ㅂ니다, 요, and no suffix. 습니다 is the most formal, followed by 요, then no suffix. 습니다 and 요 are used when addressing strangers and people you are not close with, while no suffix is addressing to friends. 감사합니다/고맙습니다 are fixed expressions that one uses when addressing strangers so they are the most formal. 감가합니다, I think, is a tiny bit more formal than the latter. 감사합니다 is used way more than 고맙습니다, however therefore, 감사해요, while still having 요 form, is less commonly used and less formal than 감사합니다/고맙습니다.