How does a chess clock work?
B · Beginner · At the board · 10 of 10Each player has a set amount of thinking time, and a chess clock with two displays counts down only for the player whose turn it is. After moving, a player presses the clock, which stops their own time and starts the opponent's. A player whose time runs out before completing the required moves loses.
How it works
- Completing a move: making the move on the board and then pressing the clock.
- Same hand: the clock must be pressed with the hand that made the move.
- Time control: a number of moves, or all the moves, in a set time, with or without extra seconds added for each move. It is fixed in advance.
- Increment: seconds added for every move.
- Delay mode: a fixed extra time each move, during which the main time does not run.
- Flag fall: the moment a player's time expires. It counts when the arbiter sees it or a player validly claims it.
- Losing on time: unless the opponent cannot checkmate by any possible series of legal moves, when the game is drawn.
- Proper handling: no pressing it forcibly, picking it up, knocking it over, hovering over it or pressing before moving.
- Pausing: only the arbiter may pause the clock, or a player who needs the arbiter's help.
The glossary has the chess clock, the time control, the increment, the flag fall, the time pressure and the arbiter.
Tricky cases
A player's time runs out in a completely winning position. Who wins?
The opponent, as long as the opponent could checkmate by some possible series of legal moves. How good the position was does not matter.
A player moves with the right hand and presses the clock with the left to save time. Legal?
No. The clock must be pressed with the same hand that made the move.
A player forgets to press the clock, and the opponent replies. Can the player still press?
Yes. A player "must be allowed to pause his/her clock after making his/her move, even after the opponent has made his/her next move".
Both flags are down and nobody knows which fell first. Who loses?
It depends. Under the guidelines for games without increment, the game continues if it is not in its final period and is drawn if it is. Those guidelines apply only where the event has announced them.
Why the rule exists
Without a clock a player in a bad position could sit and think for ever. The clock gives both players the same budget of time and makes thinking a resource to be spent. The handling rules stop the clock from becoming a second battlefield.
Where it differs
| Where | What changes | Source |
|---|---|---|
| Standard chess | 60 minutes or more for each player | FIDE Laws, Glossary of Terms ("standard chess") |
| Rapid chess | More than 10 and less than 60 minutes | FIDE Laws A.1 |
| Blitz | 10 minutes or less | FIDE Laws B.1 |
| Chess Olympiad 2026 | 90 minutes for 40 moves, then 30 minutes, with 30 seconds a move from move 1 | Olympiad 2026 Regulations 4.3.5 |
| Opponent cannot possibly checkmate | A flag fall gives a draw, not a loss | FIDE Laws 6.9 |
From the rule book
FIDE, Laws of Chess (approved 7 August 2022, applied from 1 January 2023), Article 6 and Guidelines III.3. FIDE, Chess Olympiad 2026: Regulations for the Main Competition, Article 4.3.5. Checked 14 October 2026. Official document: FIDE Laws of Chess taking effect from 1 January 2023 (FIDE Handbook E.01).