Chess Clock

How to use the chess clock

Pick a preset — bullet, blitz, rapid, or classical — or enter your own base time and increment under Time control. The base time in minutes is what each player starts with; the increment is what gets added (Fischer) or not subtracted (Bronstein / simple delay) after every move. Sudden death disables increments entirely — whoever runs out first loses.

White starts: tap White's clock face to begin. That first press starts Black's clock, matching the convention that a player hits their own side of the clock to end their turn. From then on, tap the running clock to pass the turn to your opponent; the faded clock locks and the other side starts counting down. Pause stops both clocks (useful for disputes or phone calls) and Reset puts both sides back to the base time without losing your time-control settings. When a clock reaches zero, a flag alert appears and the game is over.

Increment modes work the way you'd expect from digital chess clocks: Fischer adds the full increment to your clock every time you make a move — this is the FIDE standard for classical games. Bronstein only gives back the time you actually used, up to the increment, so your clock never gains time. Simple delay gives you a free delay window at the start of every move before your clock starts draining. The clock stays accurate even when you background the tab because the remaining time is computed from a Date.now() delta on every frame, not by counting ticks — so you can run a long classical game in a background tab without drift.