Chess Clock
Lay the phone between you and tap your half to end your move. Increment, delay, and a turn timer for board games.
Time control
Minutes each + seconds of Fischer increment per move. 90+30 adds 30 minutes after move 40.
Different minutes for White and Black give time odds, e.g. 5 against 2 for a stronger player.
Warnings
Skip takes a player out of the rotation until you tap it again; skipping the player whose turn it is passes the turn on.
How the turn timer works
Per turn gives every turn the same countdown; at 0 the panel turns red and counts the overtime until the player passes, so nobody loses a turn by accident. Whole game gives each player one bank of minutes, like a chess clock for many players: each player's time only runs on their own turns, and a player who runs out is passed over from then on.
The round goes up each time play comes back round to the first player still in the game.
How to use the chess clock
- Pick a preset such as 5+0 or 3+2, or open Custom for a delay, a second stage or different times for each side.
- Lay the phone flat beside the board. White sits at the near half; Black's half is turned round to face the far side.
- Tap Start to start White's clock (or let Black tap their half, as on a real clock).
- Make your move, then tap your own half: your clock stops and your opponent's starts. Table view fills the screen with the two halves.
- Pause stops both clocks; a flag banner appears when a clock reaches 0.
Increment, Bronstein delay and simple delay
Fischer increment adds the same time to your clock after every move, however long the move took (FIDE calls it "cumulative mode"). Bronstein delay shows your time running down as usual, then gives back what you used up to the delay, so your time never rises above where it was at the start of the move. Simple delay waits for the delay to run out before your main time starts moving; the small figure under the time counts the delay down.
Worked example on 5 minutes each. With a 3 s increment, a 10 s move leaves 4:53 (300 − 10 + 3). With a 5 s Bronstein or simple delay, a 3 s move costs nothing and leaves 5:00, and an 8 s move costs 3 s and leaves 4:57. The two delays always end on the same time; US Chess's rule book calls them "mathematically equivalent" and says they differ only in what the display shows.
Second stage. With 90+30 the clock adds 30 minutes on each player's 40th move, on top of the increment, and whatever you saved in the first 90 minutes stays on the clock: both FIDE (Article 6.3.2) and US Chess (rule 5D) carry saved time into the next period.
The time is worked out from the moment each turn started, not by counting timer ticks, so a busy or dimmed phone does not slow the clock down; the screen is kept awake while a clock runs in browsers that offer it.
What it cannot do
- No clock shared across two devices: both players use the same screen.
- It is not a certified tournament clock. For rated events use the clock the organiser approves; this one is for casual games, clubs and practice.
- It does not watch the board: it cannot tell a legal move, a draw claim or insufficient material from a flag fall.
- One extra stage at most (e.g. +30 min after move 40); no repeating controls such as 40/120 then 20/60 every 20 moves.
- A phone that is locked or has the browser closed keeps the time correct, but cannot beep or vibrate until it is opened again.
Privacy and what is stored
Nothing you type leaves your device. The clocks, the board game names and colours, and your settings are saved in this browser's local storage so an accidental reload does not lose a game; Clear saved clocks deletes all of it in one tap. The page sends an anonymous page-view count and, at most, two fixed words (clock-start and clock-boardgame), never a name or a time.
Questions
Can I use this chess clock online on one phone?
Yes. Open the page on one phone or tablet, lay it flat between the two players and tap Start. The far half is turned round so the opponent reads their own time the right way up; each player taps their own half to end their move. Table view hides everything else on the screen. It is one device: two phones cannot share one clock.
What is the difference between increment and delay?
Increment (Fischer) adds the same time after every move however fast you were, so a quick player builds up time: 5 min + 3 s and a 10 s move leaves 4:53. Delay never adds time above where you started the move: with a 5 s delay a 3 s move costs nothing and an 8 s move costs 3 s. Bronstein and simple delay cost exactly the same; Bronstein shows the time running down and refunds it, simple delay waits before the main time starts.
What are the chess clock rules?
Make your move, then press your own clock with the same hand, which starts your opponent's. Under FIDE's Laws (Article 6) a player whose flag falls loses, unless the opponent cannot checkmate by any series of legal moves, in which case it is a draw. In a control such as 90 min for 40 moves, time you save carries into the next stage. This clock shows the flag; deciding the result stays with the players or the arbiter.
Can I use it as a board game timer?
Yes. Switch to Board game, choose 2 to 8 players, give them names and colours, and pick either a countdown for each turn (say 60 seconds) or a total time per player for the whole game. Tap the big panel to pass to the next player, skip anyone who is sitting out, and the round counter goes up each time play comes back to the first player.
Which time control should I pick?
US Chess recommends an increment or delay of 2 s for a base time of 10 minutes or less, 3 s for 10 to 30 minutes, and 5 to 30 s for 30 minutes or more. 3+2 and 5+0 are blitz, 10+5 and 15+10 rapid, and 90+30 with 30 more minutes after move 40 is FIDE's usual classical control.