Although Lichess isn't perfect and it's kinda annoying. One of the bad things about Lichess is how unrealistically inflated their ratings are; 2100 on Lichess is equivalent to about 1800 on Chess.com. Chess.com is much more similar to the FIDE rating and other real-world systems. Lichess is just super inflated for some reason and it makes it kinda hard to compare your progress to other metrics.
There's also https://chessgoals.com/rating-comparison if you prefer a table
- they use different rating systems (Elo for FIDE, Glicko-2 for LiChess and afair, Glicko/Glicko-2 for chess.com)
- ELO / Glicko rating is calculated for a _player pool_. Which means it will never correspond between FIDE-registered players and chess websites because they don't have the same player base.
It has nothing to do with being “inflated” or “unrealistic”. The difference is “by design”
150 Elo on levels below 2700 FIDE is almost night and day difference.
Chess.com ratings show nothing about theoretical FIDE ratings. Comparison tables have been built with data mining and lucky guesses, there's no quality difference between Chess.com <-> FIDE and LiChess <-> FIDE.
It's just a fact that chess.com ratings are closer to 'real' ratings than Lichess are. It's not perfect but that doesn't mean it's a zero-information statement either.
Of course these things are correlated, but e.g. there have been times in the world championship when one of the players thought about a position for 20+ minutes before making a move. That's hard to do, and requires very strong visualization skills.
Lichess is overall better in my opinion, better & slicker product, free analysis, opening explorer etc. Chess.com only leads in video content imo.
With rating systems, the absolute scale doesn't matter, all that matters is the predictive power of the system. Every time I have benchmarked, glicko does a better job in predicting win/loss/draw probabilities than ELO ratings used by FIDE.
If you want to know your rating relative to other players on the site, you can check the distributions here [2]. If you want to compare them to FIDE ELO, or chess.com, you can use this site although I am not sure about exactly what methodology they use [3].
I wouldn't agree that lichess ratings are inflated or unrealistic relative to FIDE Elo, or any other rating system any more than kilometers are unrealistic and inflated relative to miles. They are simply different measurement systems.
[1] http://glicko.net/glicko/glicko2.pdf