Online chess platforms handle time controls differently from each other and differently from FIDE’s official definitions. The same control can be labelled blitz on one site and rapid on another. Ratings earned at one time control do not transfer across categories. Understanding how the platforms work stops you accidentally playing in the wrong format — and explains why your online rating and your over-the-board rating can look so different.
How platforms estimate game length
FIDE defines time control categories by the time each player starts with. Under FIDE rules, blitz is more than 3 and up to 10 minutes per player; rapid is more than 10 and under 60 minutes. A 10+0 game is rapid. Simple.
Online platforms generally do not use that rule. Instead, they estimate the total expected game length and categorise based on that. The most common formula is:
estimated duration = starting minutes + (increment seconds × 40)
The 40 represents a rough expected game length in moves. So a 5+3 game is estimated as 5 + (3 × 40 ÷ 60) = 7 minutes — blitz. A 10+5 game is estimated as 10 + (5 × 40 ÷ 60) ≈ 13.3 minutes — rapid. The increment pulls the category upward compared to a FIDE reading of the same numbers.
This matters in practice: a 10+0 game is rapid everywhere, but a 10+5 game might be labelled differently on different platforms depending on their exact formula.
Chess.com categories
Chess.com uses the following category thresholds (approximate, based on estimated game duration):
- Bullet — under 3 minutes estimated
- Blitz — 3 to under 10 minutes estimated
- Rapid — 10 minutes and above
Chess.com separates each category into its own rating pool. Your blitz rating has nothing to do with your rapid rating, which has nothing to do with your bullet rating. Each pool is a separate ladder, and you earn or lose points only within the pool for the format you played.
Chess.com also runs Daily chess — correspondence-style games where each player has days rather than minutes. These have their own separate rating and are not a time control in the classical sense.
Lichess categories
Lichess uses a slightly different structure. Its categories are:
- UltraBullet — under 30 seconds estimated
- Bullet — 30 seconds to under 3 minutes estimated
- Blitz — 3 to under 8 minutes estimated
- Rapid — 8 to under 25 minutes estimated
- Classical — 25 minutes and above
Lichess gives each category its own rating pool, same as Chess.com. A notable difference is that Lichess has a UltraBullet pool for the very fastest controls (like 1+0), which Chess.com groups into bullet.
Lichess also offers Correspondence games with its own separate rating, and a Chess960 variant (Fischer Random) that runs its own pools by time format.
Why your rating looks different across platforms
Several things explain rating differences between platforms:
Different player pools. Lichess and Chess.com have large but different populations. Rating inflation and deflation vary independently on each platform. A 1500 on Lichess and a 1500 on Chess.com are not equivalent because the distributions are different.
Different rating systems. Lichess uses the Glicko-2 system with a rating deviation component, which means new ratings start around 1500 but shift quickly. Chess.com uses a modified Elo-like system. The mechanics of how ratings change after each game differ.
Different category definitions. If you mostly play 10+5 rapid on Chess.com but on Lichess that format falls in the rapid pool while some of your habits were built on blitz timings, the mismatch can affect results.
Different player base at specific controls. A 3+2 blitz player on Lichess competes in a pool that includes a large proportion of dedicated tactical players. The same person playing 3+2 on Chess.com might be in a slightly different competitive environment.
Online categories vs FIDE definitions
The disconnect between online labels and FIDE definitions causes confusion, particularly around “blitz” and “rapid.” The practical consequence:
- A game you played as “rapid” on Lichess (8-minute estimate) would be FIDE blitz.
- A game you played as “rapid” on Chess.com (10-minute estimate) would be FIDE rapid.
- Your rapid rating on Chess.com is built on games that FIDE would count as rapid. Your rapid rating on Lichess is built partly on games FIDE would count as blitz.
For over-the-board rated play, only FIDE (or your national federation’s) definitions matter. Online platforms use their own systems purely for matchmaking and rating pool management.
Correspondence and Daily chess
Correspondence chess — where each player has days or weeks per move rather than minutes — has a long tradition predating online play, conducted by post and then email. Both Lichess and Chess.com offer it as a separate format with dedicated ratings.
It is a fundamentally different game from timed chess: analysis engines are expected to be used on most platforms (or at least very difficult to prevent), games last weeks or months, and the skills required are more about deep preparation and endgame technique than rapid pattern recognition. If you enjoy it, treat it as a separate hobby alongside timed chess rather than a slower version of the same thing.
Playing the same time control on different platforms
If you want consistent experience, stick to controls that fall clearly within one category on both major platforms. Controls that behave consistently:
- 1+0 and 2+1 — bullet everywhere
- 3+0 and 3+2 — bullet/blitz, consistent across platforms
- 5+0 and 5+3 — blitz everywhere
- 15+10 and 25+10 — rapid everywhere
Controls in the 8-12 minute range with moderate increment are the ones that fall differently depending on the platform formula. If consistency matters to you, stay away from the edges.
Using the online clock for OTB preparation
One practical use of an online clock is preparing for an over-the-board format you do not play often. If you usually play online at blitz speeds but have a rapid tournament coming up, practising at 15+10 on a real clock — rather than on a platform that handles the timing for you — builds familiarity with the physical rhythm: pressing after each move, watching your own clock rather than a screen prompt, feeling the pressure differently.
The online clock matches the over-the-board experience more closely than a platform game because you are managing the press yourself and watching a real countdown, which is exactly what you will do at the board.