How to use the chess clock
- Pick a preset such as Blitz 5+3, or type Minutes per side and Increment (seconds per move), then choose the Clock type.
- Press Start, or tap Black's side, to start White's clock.
- After each move, tap your own side or press Space. Your clock stops, your increment or delay is applied, your move count goes up and your opponent's clock starts. Tapping the other side does nothing.
- Pause freezes both clocks and Reset starts over. When a clock reaches 0:00.0 the game stops and that side shows Out of time.
Increment and delay, explained
- Fischer increment (the default) adds the full increment to your clock after every move, so unused time banks.
- Bronstein delay counts down from the start of your turn, then gives back the time you used, up to the delay.
- Simple delay holds your clock still for the delay each turn, then counts down. Unused delay is lost (Time control).
FIDE sorts a game by its main time plus 60 times the increment: more than 3 and up to 10 minutes is blitz, and more than 10 and under 60 is rapid (Rapid and Blitz regulations). So 5+3 counts as 5 + 3 = 8 minutes, which is blitz, and 10+5 is 15 minutes, which is rapid.
Worked example
With the defaults, 5 minutes and a 3 second Fischer increment, both sides show 5:00 and 0 moves. White thinks for 12 seconds and taps: 5:00 - 0:12 + 0:03 leaves 4:51 and White shows 1 move. Black thinks for 20 seconds and taps: 5:00 - 0:20 + 0:03 leaves 4:43. A move made in 2 seconds would leave White on 5:01 with Fischer, but 5:00 with either delay type.
Limits and edge cases
- The clock reports that time ran out, but the result depends on the rules: a player whose flag falls loses unless the opponent cannot checkmate by any legal moves (FIDE Laws, Article 6.9).
- Only one main time plus an increment or delay is supported. Controls that add time after move 40 are not, so Classical 90+30 is the main time plus increment only.
- Time is measured from your device's clock, so it stays correct if the page is slow, but the display only updates while the tab is visible. The page asks for a screen wake lock where the browser allows it.
- Playing with a timer on your own? Try the countdown timer, the stopwatch or the multi timer.
Frequently asked questions
What does 5+3 mean on a chess clock?
Each player starts with 5 minutes, and 3 seconds are added to their clock after every move they make. This is the Fischer increment, named after Bobby Fischer, and it means a few seconds are banked with each move.
What is the difference between increment and delay?
Increment adds time to your clock after you move, so unused time carries over. Simple delay holds your clock still for a few seconds at the start of each turn, and any delay you do not use is lost. Bronstein delay gives back the time you used, up to the delay.
Who starts the clock in chess?
White's clock starts first. Press Start, or tap Black's side the way Black would press their own button on a physical clock, and White's time begins to run.
What happens when time runs out?
The clock stops and that side shows Out of time. Under FIDE rules the player who ran out loses, unless the opponent could not checkmate by any series of legal moves, in which case the game is drawn.
Sources: Wikipedia, Time control; FIDE Rapid and Blitz Rating Regulations; FIDE Laws of Chess. Checked October 2026.