Chess clock
Put the phone between two players and tap your own side after each move. Choose a preset like 5+0 or 15+10, or set your own minutes and seconds, with the extra seconds added after every move or used as a delay. It works for chess, Scrabble, Go and any other timed game.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Pick a time control or enter your own minutes and seconds, then choose whether the seconds are added after each move or used as a delay.
- Player 1 sits at the bottom and Player 2 at the top. The top half is turned upside down so the opponent can read it.
- Make a move, then tap your side. The other clock starts.
- Use Pause to stop both clocks and Reset to start again with the same settings.
How it works
The clock records the time of each update from the browser’s monotonic timer and takes the difference from the running side, so the display does not drift the way counting intervals would. With an increment, the seconds are added after your press. With a delay, the delay is spent first each turn and only then your main time. When a side reaches zero, both clocks stop and that side shows Time is up.
Example
5+3 is five minutes each with 3 seconds added per move. If you use 4 seconds on a move you are 1 second down; if you use 1 second you gain 2.
Tips
- Use a delay for over-the-board play where you do not want time to grow.
- Changing the time resets the clock.
- Keep the phone flat, so the upside-down half reads correctly.
Frequently asked questions
What do 5+0 and 15+10 mean?
The first number is the starting time in minutes for each player, the second is the seconds added after each move. So 15+10 gives 15 minutes and 10 seconds more after every move. 5+0 is five minutes with no addition.
What is the difference between increment and delay?
With a Fischer increment, the seconds are added to your time after you move, so your time can grow. With a delay, the clock waits that many seconds at the start of each turn before it begins to count down, and unused delay is lost. Delay never adds to your time.
How does the first tap work?
The first tap, on either side, starts the other player's clock and counts no move. Normally White moves first, and Black taps their own side to start White's clock, or the reverse if you agree so.
Does the screen stay awake?
While a clock is running the page asks the browser to keep the screen on. Browsers without this feature, or with it blocked, may dim or lock the screen on their normal timeout. Pausing releases it.
Will the clock keep time if I switch tabs?
Time is measured from the browser's own clock, not by counting ticks, so a clock that was running stays correct when you come back. Some phones throttle a hidden page, so keep the page open while you play.