What happens when your time runs out in chess?

Your flag falls and you lose the game — unless your opponent has no possible way to deliver checkmate by any legal sequence of moves (for example, only a bare king remains). In that case the game is drawn instead.

Do you press the chess clock before or after moving?

After. Your clock runs until you complete your move on the board and then press your button, using the same hand that moved the piece.

When was the chess clock invented?

Sandglasses were first used to time tournament chess in 1862, and the first true mechanical double chess clock, built by Thomas Wilson of Manchester, appeared at the London 1883 tournament. Digital clocks with increments followed Bobby Fischer's 1988 patent.

Why is it called 'flagging' someone?

Mechanical clocks had a small flag that the minute hand lifted as it approached the hour; when time expired the flag fell. Winning on time is still called flagging, even on digital clocks with no physical flag.

Who starts the chess clock at the beginning of a game?

Black starts White's clock (or the arbiter does at the scheduled start time). White's thinking time counts from that moment, even before the first move is played.

How a chess clock works: rules, history, and how to use one

A chess clock is two linked timers, one per player, arranged so that only one runs at a time. After completing a move you press your side of the clock, which stops your timer and starts your opponent's. If your time runs out — your flag falls — you lose the game, unless your opponent lacks any possible way to checkmate you, in which case it is a draw.

Two clocks, one running

The core mechanism has not changed since the 19th century: two timers are mechanically or electronically linked so that starting one stops the other. Your clock runs while you think; the moment you complete your move and press your button, the burden — and the ticking — passes to your opponent.

Both players receive the same total budget (unless odds are agreed), but how they spend it is up to them. That is the beauty of the device: time becomes a resource you manage like material or position. Spend twelve minutes on a critical middlegame decision and you may face the endgame with seconds; blitz out known theory and you bank time for later.

The rules of using a clock

The essential clock rules, drawn from FIDE's Laws of Chess and USCF practice:

Move first, then press. Your clock keeps running until you have completed the move on the board and pressed your button. You may not press before moving.
Same hand. You must press the clock with the same hand you used to move the piece. Moving with one hand and slapping the clock with the other is illegal.
No hovering or holding. Keeping a finger resting on or above the button is forbidden, as is picking the clock up.
Black starts the clock. At the agreed start time, Black (or the arbiter) starts White's clock.
Flag fall loses — usually. Running out of time loses the game, except when the opponent cannot possibly checkmate you by any legal sequence of moves — a lone king, for instance. Then the game is a draw, not a loss.
Illegal moves cost time. In FIDE classical play, an opponent's first illegal move earns you two extra minutes; a second illegal move by the same player loses them the game. Blitz and rapid have their own stricter variations.

A short history: from sandglasses to Fischer's patent

Timed chess is older than most players realize:

1862: the London–anywhere problem of interminable games (one 1851 tournament game reportedly saw a single think of over two hours) led organizers to time players with sandglasses — one per player, tipped on its side when it was not your turn.
1883: the London tournament introduced the first practical mechanical double clock, built by Thomas Wilson of Manchester: two pendulum clocks on a see-saw beam, so tilting one stopped it and started the other. Button-operated versions soon followed.
Around 1900: the flag was added — a small lever lifted by the minute hand as it approached twelve, whose fall marked the exact moment time expired. The phrase "flagging" survives long after the physical flag disappeared.
1988: Bobby Fischer patented a digital clock that added a small increment after every move, attacking the ugly time scrambles that decided sudden-death games. Fischer's idea, once controversial, is now the world standard.
Today: digital clocks — and phone apps — handle increments, delays, and multi-phase controls no mechanical clock could, with precision to fractions of a second.

Reading a time control

Time controls are written compactly, and the notation is worth learning:

Written as	Meaning
5+0	5 minutes per player, no increment (sudden death)
3+2	3 minutes plus 2 seconds added after every move (Fischer increment)
G/30 d5	USCF style: game in 30 minutes with a 5-second delay before each move's time starts counting
90/40 + 30, +30s	Multi-phase: 90 minutes for the first 40 moves, then 30 more minutes for the rest, with 30 seconds added every move — the FIDE classical standard

The bonus systems differ in spirit: a Fischer increment is added outright and can grow your clock; a delay (or its Bronstein equivalent) merely protects you from losing time on quick moves. Our Fischer and Bronstein guides cover the distinction in depth.

Analog versus digital — and the phone in your pocket

Analog clocks are lovely objects, but they cannot do increments or delays, their flags are imprecise, and the modern game has largely left them behind: today's standard controls simply require digital timing. A digital clock — hardware or app — shows exact seconds, applies bonuses automatically, and enforces multi-phase controls without anyone counting moves on their fingers.

A phone app like Chess Clock is the most accessible way to learn all of this. The presets encode the real controls (blitz, rapid, FIDE and USCF tournament settings), each half of the screen faces its player, and the game history afterward shows exactly how each of you spent your time — the fastest way to learn better clock management. See our guide on why a chess clock app is worth using for the full picture.

Turn your iPhone into a real chess clock

Chess Clock gives you every time control from Bullet to FIDE Classical — beautiful, precise, and completely private.

Coming soon to the App Store