How does chess.com ratings compare with FIDE ratings?

Idk I don't get time to play since I am busy with my studies.

hello how are points calculated in tournaments?

Considering different thinking times while comparing online with otb does make no sense. I'm just 400 points better in rapid than in bullet. So only compare otb blitz to online blitz, etc.

Putting aside that some individuals might play better otb and some may play better online, the overall gap between top players FIDE and chess.com blitz rating is about 350 points. (rough average of Magnus, Fabiano, Firouzja, Sahin...). So: chess.com - 350 = FIDE for top blitz players. It may be a smaller gap though, once you get to lower ratings.

I am a 900 in chesscom but rated 1479 on

Check rules B.7.2.7.1.4 and B.7.2.8.2 for new players and rules B.7.2.7.1, B.7.2.8.3 and B.7.2.8.1 for players after achieving their first rating.

Follow this link: FIDE Handbook