My rapid rating started at 100
How does chess.com decide initial ratings?

My rapid rating started at 100
Nope, it started at 400, but you lost 300 in your first game, so it was 100 after your first game. But before that game it was 400.

guys, i have a question. Is there a tool to know my rating if I play only like 6-8 moves? Can it be applied to any 6-8 moves in an n move game??
I must have chosen "New to chess", I mean that's what I was. But I didn't start at 400, looking at the history the first game I can see I was at 281 (I'm not sure it's the very first game, the date I registered tells me that I must have done a few games prior to that so I could have started even lower). Why is that?
I must have chosen "New to chess", I mean that's what I was. But I didn't start at 400, looking at the history the first game I can see I was at 281 (I'm not sure it's the very first game, the date I registered tells me that I must have done a few games prior to that so I could have started even lower). Why is that?
The only ratings shown are post game. You did start at 400 with a very unsubstantiated rating and your first loss to a 441 changed your opponent's rating to 477 and yours to 243. The first few games can see major swings in your rating until you start settling down.

Jeez, I noob screwed this question up twice now. Okay, a search tells me everyone should start with 1200. I thought I started with 800 but that was with a bot. My profile shows I started at 1089 and increased 177 in the past month to my current 1266. I have seen people at 400 though.
When you create an account you choose a skill level and that translates to a default rating:
- New to chess: 400
- Beginner: 800
- Intermediate: 1200
- Advanced: 1600
- Expert: 2000
https://support.chess.com/article/671-how-do-i-create-an-accoun
Facinating.
I dont remember this question even being asked.
Also I have no clue what my rating is anyway.
But it explains why my opponents still blunder so much, even around rating 1000.

@Martin_Stahl response was correct back in early 2021 when that was written; chess.com has since "upgraded" to this newer way of getting to an accurate rating more efficiently.
Aaaaah ok yeah thats what I remember.

I must have chosen "New to chess", I mean that's what I was. But I didn't start at 400, looking at the history the first game I can see I was at 281 (I'm not sure it's the very first game, the date I registered tells me that I must have done a few games prior to that so I could have started even lower). Why is that?
The only ratings shown are post game. You did start at 400 with a very unsubstantiated rating and your first loss to a 441 changed your opponent's rating to 477 and yours to 243. The first few games can see major swings in your rating until you start settling down.
Correct. If you look at the game, it shows a rating of 243 for you - but this is the rating you had after the game.
If you go to the game and look at the Info tab, you can see the rating adjustment you got from that game: -157 for you, +36 for your opponent.
400 - 157 = 243. So you started with 400, lost 157, and that left you with 243.
I was not given the option to choose what should I do?
You probably said you were new to chess and were then assigned 400. You don't get a number to choose, just a description that ends up corresponding to a number. The descriptions are a little vague (I misinterpreted them and started more the 600 points too low) but they are also considered unsubstantiated and can have major swings at the beginning while zeroing in on your strength.
Just play and you will fairly quickly get to your rating strength.

I won my first 5 games with a performance rating of 1300-1400 and at the end I was given a rating of 855
If you're using the Game Review report card as your performance rating, that's just an estimate and isn't an actual rating strength.
I was not given the option to choose what should I do?
You probably said you were new to chess and were then assigned 400. You don't get a number to choose, just a description that ends up corresponding to a number. The descriptions are a little vague (I misinterpreted them and started more the 600 points too low) but they are also considered unsubstantiated and can have major swings at the beginning while zeroing in on your strength.
Just play and you will fairly quickly get to your rating strength.
I won my first 5 games with a performance rating of 1300-1400 and at the end I was given a rating of 855
You started at 400 and gained: 150; 133; 63; 69; 57; 8 (draw against a higher rated player); 67; 52; 53. 400 seems a bit low for a stronger player so you might have mis-guessed where you should have started (like I did).
Aren't ratings decided on your first five games I played 3 blitz and 2 rapids but I'm unsure if my rating is permanent or not
You are correct, it takes 5 or more games to display your rating.
@Martin_Stahl response was correct back in early 2021 when that was written; chess.com has since "upgraded" to this newer way of getting to an accurate rating more efficiently.
Huh. I joined mid-late 2024 and I put myself as a beginner, it put my initial rating as 800.
Maybe that's only updated recently.
select a skill level and it will give you 400, 900, 1200, or 2000