Chess Clock
This chess clock gives each player a clock of their own: when you have moved, tap your side or press a key, and your clock stops while your opponent’s starts. Set the time per player and an optional increment or delay, and the clock marks a flag when a player’s time runs out.
To start, the player who moves second taps their side.
Time control
Bullet
Blitz
Rapid
Classical
Custom
Options
Used when the clocks are stacked, on a phone or tablet held upright.
Keyboard: Space ends the running player’s turn, and before the game it starts Player 1’s clock. Player 1 can also press ← or ↓, and Player 2 → or ↑. P pauses and resumes; R resets while the clock is stopped.
How to use the clock
Put the phone, tablet or laptop between the two players and choose a time control: the minutes each player has for the whole game, and the seconds added after every move, if any. In over-the-board chess the player with the black pieces starts White’s clock, and from then on each player stops their own clock straight after moving, which starts the opponent’s.
Only one clock runs at a time, and the side that is running is the one that is highlighted. Tap your half of the screen, or use the keyboard, to end your turn. Pause stops both clocks for a question, a dispute or a break, and nothing is lost when you carry on. When a clock reaches zero it shows that the player is out of time, with a sound if you want one, and the game is decided by the players, as it is with a physical clock.
On a phone or tablet held upright the two clocks are stacked, and the top one is turned round to face the player across the table, so the device can lie flat between you; on a wider screen they sit side by side. Each side counts its own moves. The screen is kept on while a clock runs where the browser allows it, and a reload in the middle of a game carries on with the right time.
Time controls, increment and delay
Time controls are written as two numbers: 5+3 means five minutes on each player’s clock and three seconds added after every move. The added seconds are the increment, sometimes called Fischer time after Bobby Fischer, who proposed it; they let a player who moves quickly bank time, and they stop a won position being lost purely on the clock in the final seconds. A control with no increment, such as 5+0, is called sudden death.
Under FIDE’s Laws of Chess a blitz game gives each player ten minutes or less, counting sixty moves’ worth of increment, and a rapid game gives more than ten minutes and less than sixty. The presets are grouped by that rule, so 10+0 counts as blitz here, although some sites call it rapid. Bullet, under three minutes, is not a FIDE category, but it is the usual name for the fastest games.
Some clubs use delay instead of increment, and the clock offers both kinds. With simple delay the clock waits a few seconds at the start of each move before it counts down; with Bronstein delay it counts down at once and gives back the time the move took, up to the delay. Either way a player cannot build up time. In the last ten seconds the clock shows tenths. Check which rule an event uses before you set the clock.
Beyond chess
Any game in which two players take turns, and each should have a fair share of the time, can use a chess clock: draughts and checkers, Go, Scrabble, backgammon and many modern board games, as well as practice for a two-person debate. The clock does not know the rules of the game on the table; it only makes sure that thinking time is spent on your own turn and shows exactly how much each side has left.
The clock runs in your browser with nothing to install and no account, and the settings you use most are remembered on your own device. For timing a whole session rather than two players, the stopwatch and the timer are simpler.
Questions and answers
How does a chess clock work?
It holds two clocks and runs only one at a time. When a player has moved, they press their side, which stops their clock and starts their opponent’s, so each player spends time only on their own turns.
What does 3+2 mean in chess?
Three minutes on each player’s clock, with two seconds added after every move they make. The first number is minutes per player, and the second is the increment in seconds.
What is the difference between increment and delay?
Increment adds a fixed number of seconds to your clock after each move, so time can build up. Delay waits a fixed number of seconds before your clock starts counting down on each move, and never adds more than it waited, so time cannot build up.
Who starts the clock in chess?
The player with the black pieces starts White’s clock, which begins the game. After that, each player presses their own side after moving.
What happens when a player’s time runs out?
That player loses on time, called a flag fall, unless the opponent cannot possibly checkmate, in which case the Laws of Chess make the game a draw. The clock marks the flag, and the result is for the players to record.
Can two players share one phone as a chess clock?
Yes. Open the clock with the phone upright and lay it flat between you: the screen splits into two large halves, and the far half is turned round to face your opponent. Each player taps their own half after moving.