How to use a chess clock, step by step

How does a chess clock work?

A chess clock is two timers joined so only one runs at a time. While you think, your time goes down. When you finish your move you press your button, your clock stops and your opponent's starts.

The number before the plus sign in a name like 5+0 is minutes per player for the whole game. The number after it is seconds added per move, which is covered in the Fischer increment guide.

How to use the chess clock app, step by step

1. On the home list, tap Blitz 5+0 under Built-in. The Setup screen shows the time control and a one-line explanation of the mode.
2. Under Players, type names into White and Black. White's half is the upright one, at the bottom in portrait. Turn on Swap Sides on Screen if White sits at the other end.
3. Pick a Flag Alert Sound and leave Haptics on if you want a short vibration on every press.
4. Tap Start Game and lay the phone flat beside the board, one half facing each player. The screen reads Tap either side to start.
5. Start White's clock with a tap on either half. At a club, Black usually does this once both are ready.
6. White moves, then taps the White half. Black's clock starts. Keep alternating: move, then tap your own half.
7. The Move number on each half counts that player's completed moves.

What the screen tells you during the game

The half whose clock is running has a coloured border, so a glance tells you whose move it is.

What happens when time runs out in chess?

Running out of time is called a flag, after the little flag that falls on a mechanical clock. Under normal rules the player whose time runs out loses, unless the opponent has no way to checkmate, in which case it is usually a draw.

In the app, the moment a clock reaches zero that half shows FLAG, the other player is shown as the winner on time, the alert plays once and the game goes to History with Saved to History on screen. Tap Done to return to the list. The app does not look at the board, so if the position should be a draw, agree that between you.

Undo, pause and leaving a game

The four round icons in the middle of the screen are undo, pause, reset and leave.

• Undo reverses the last accepted tap: time, move count and turn. It goes back one step only.
• Pause freezes the running clock and shows Paused. Tap Resume to continue with no time lost or gained.
• Reset opens Reset Game? and puts both clocks back to the start. The game is not saved.
• Leave (the X) opens End Game? once a move has been played: pick a winner or Draw to save it, or Discard Game.

Common beginner mistakes

• Forgetting to press. Your clock keeps running until you tap your own half, even if you already moved.
• Pressing the other side. On this clock that does nothing, so nobody's time jumps.
• Double-pressing. A second tap within 0.15 seconds is ignored, so a nervous double tap still counts once.
• Walking away with the clock running. Time is measured from timestamps, so it keeps counting while you take a call. Pause first.

The screen will not lock during the game, because auto-lock is switched off while the clock is open.

Questions and answers

You might also like

• Fischer increment in chess: what 3+2 and 15+10 mean · Chess Clock
• Chess time controls explained, and how to set any of them · Chess Clock
• See your time per move in chess, move by move · Chess Clock

More Chess Clock guides

• Fischer increment in chess: what 3+2 and 15+10 mean
• Chess increment vs delay: Fischer, Bronstein and US delay compared
• Chess time controls explained, and how to set any of them
• See your time per move in chess, move by move
• A two-player turn timer for board games
• What chess timer settings suit kids?
• Why is my chess clock counting up?
• How to pause a chess clock
• All questions about Chess Clock
• Back to Chess Clock