The Chess Timer

How Does a Chess Clock Work?

Published September 28, 2026 · 10 min read

So how does a chess clock work? It is two timers joined so that only one can run at a time. After you make a move you press your side of the clock: your time stops and your opponent’s time starts. If your time runs out before the game is over, you normally lose. Everything else in this guide (setting the clock, what “3+2” means, increment and delay) is a refinement of that one mechanism.

What is the point of a chess clock?

Without a clock, a game of chess takes as long as the slower player wants it to. A clock gives both players the same amount of time, turns that time into a resource, and lets an organizer promise that a round will finish on schedule.

The FIDE Laws of Chess put it this way: “each player must complete a minimum number of moves or all moves in an allotted period of time including any additional amount of time added with each move. All these must be specified in advance” (Article 6.3.1). The US Chess rulebook says the same in its own words: each player must make a certain number of moves, all moves, or all remaining moves in an allotted period of time, “these factors being specified in advance” (Rule 5A).

The clock also gives the game one more way to end: running out of time, called a flag fall. That is what makes fast chess possible. As US Chess notes about five-minute blitz, “each game takes only about 10 minutes” (Chapter 11).

What is the rule of a chess clock?

These are the chess clock rules that come up in almost every game. The wording follows the FIDE Laws (Article 6) and the US Chess rules (Rules 5, 13 and 16); where the two differ, both are given.

  1. Move first, then press. “During the game each player, having made his/her move on the chessboard, shall pause his/her own clock and start his/her opponent’s clock (that is to say, he/she shall press his/her clock). This ‘completes’ the move” (FIDE 6.2.1). The seconds between placing the piece and pressing the clock are yours (FIDE 6.2.2).
  2. Press with the hand that moved. “A player must press his/her clock with the same hand with which he/she made his/her move” (FIDE 6.2.3; US Chess 16C1 says the same), and each move is played with one hand only (FIDE 4.1). You may not keep a finger on the clock or hover over it, press it forcibly, pick it up, press before moving, or knock it over (FIDE 6.2.3–6.2.4; US Chess 16C, 16C2).
  3. White’s clock starts first. “At the time determined for the start of the game White’s clock is started” (FIDE 6.6; US Chess 16I). On The Chess Timer, Black taps first, which starts White’s clock.
  4. A flag fall means your time is up. FIDE defines ‘flag-fall’ as “the expiration of the allotted time for a player” (6.1); digital clocks show it as all zeros, a light or a beep (US Chess 5G). Who may point it out differs: under FIDE a flag has fallen “when the arbiter observes the fact or when either player has made a valid claim” (6.8); under US Chess rules “only the players in a game may call attention to the fall of a flag” and “a director must never initiate a time-forfeit claim” (13C1). US Chess lists this first in its own FIDE comparison sheet.
  5. Running out of time usually loses. Under FIDE, “if a player does not complete the prescribed number of moves in the allotted time, the game is lost by that player. However, the game is drawn if the position is such that the opponent cannot checkmate the player’s king by any possible series of legal moves” (6.9). US Chess handles the insufficient-material case differently (Rule 14E); see FIDE vs US Chess (USCF) clock rules compared.
  6. The clock is trusted unless it is visibly broken. “Every indication given by the chessclock is considered to be conclusive in the absence of any evident defect” (FIDE 6.10.1).

Casual games can relax any of this, but if you press with your moving hand from the start you will never have to unlearn it.

How do you set a chess clock?

Every chess clock, physical or in a browser, is set with the same three decisions:

  • Base time: how many minutes each player starts with, for example 5, 15 or 90.
  • Added time per move: none, an increment (time is added after each move) or a delay (the clock waits before it counts down). See below and Increment vs delay.
  • Seconds per move for that increment or delay, typically 2, 3, 5, 10 or 30.

Under US Chess rules the clock is set “according to the director’s instructions, with the time delay or increment in force starting at move one”, and “players should explain the flag fall mechanism and the clock’s operation to their opponents” (Rule 16B2).

On The Chess Timer the same decisions look like this:

  1. On the home page, tap a preset in the Time controls grid: 1+0, 3+2, 5+0, 5+3, 10+0, 15+10, 30+0 or 90+30. The clock opens ready to start.
  2. For anything else tap Custom. In Clock settings, set the Base time (both players), choose Added time per move (None, Fischer, Bronstein or Delay) and the Seconds per move. Switch on Different time for Black to give one player more time, or add a Stage (“e.g. after move 40, add 30 min”). The Armageddon switch sets White 5:00 and Black 4:00. Tap Save and start.
  3. Lay the phone or tablet flat between you. In the Face to face layout each player’s time is turned toward them; on a laptop use Side by side.
  4. Black taps their half of the screen (it says Tap to start), and White’s clock runs. After each move, tap your own half. On a keyboard, Space presses the clock for the player to move; in the side-by-side layout Left Shift and Right Shift press for the left and right player.
  5. Pause (or P) opens a panel with Undo last tap, Adjust time, Settings and Reset clock (R).

The clock also offers a Low-time warning (off, 10 s or 30 s) and Show tenths under 20 seconds, and it keeps the screen awake while running in browsers that support it.

How does 3+2 time work in chess?

“3+2” is shorthand for 3 minutes of base time and a 2-second increment: after every move you complete, 2 seconds are added to your clock. FIDE’s glossary describes the same idea for a slower game as “all the moves in 30 minutes, plus 30 seconds cumulatively from move 1” and calls it the cumulative or Fischer mode, “where a player receives an extra amount of time (often 30 seconds) prior to each move”. US Chess writes the same control as G/3 inc/2 or G/3 +2 (Rule 5B2).

Move in under 2 seconds and your time goes up; a long think costs you the difference. The increment never runs out, so a simple endgame can be played out with quick moves instead of being lost on the clock. That is what the increment is for.

One detail is worth knowing before you play in a club: the increment is due for move one as well, so a 3+2 clock should start at 3:02, not 3:00. FIDE’s glossary describes the increment as time “added from the start before each move”, FIDE’s standard for electronic chess clocks says that in Fischer mode “the increment must be added before the first move” (C.02/03, section 3.3.3), and the US Chess rulebook tells directors to add it by hand on clocks that don’t, “for example, for G/3;inc2, each player gets 3.02 (three minutes and two seconds) to complete move one” (Rule 16B2, TD tip). The Chess Timer does what a tournament clock does: choose 3+2 and the display reads 3:02 before the first move.

Is 3+2 blitz? Yes, under both rule sets. FIDE counts a game as blitz when “the allotted time plus 60 times any increment is 10 minutes or less for each player” (Appendix B.1): 3 minutes + 60 × 2 seconds = 5 minutes. US Chess adds base minutes and increment (or delay) seconds, “mm+ss” (Rule 5C): 3 + 2 = 5, and “G/3 inc/2 – Blitz” is in its list of examples. All the categories are in Chess time controls explained.

Here is how the common notations read:

Written as Meaning Total per player (base + 60 × increment)
1+0 1 minute, nothing added 1 min, blitz under FIDE (platforms call it “bullet”)
3+2 3 minutes, 2 seconds added after every move 5 min, blitz under FIDE
5+3 5 minutes, 3 seconds added after every move 8 min, blitz under FIDE
10+0 10 minutes, nothing added 10 min, blitz under FIDE
15+10 15 minutes, 10 seconds added after every move 25 min, rapid under FIDE
25+10 25 minutes, 10 seconds added after every move 35 min, rapid under FIDE
90+30 90 minutes, 30 seconds added after every move 120 min, standard under FIDE
90/40 + 30, +30 90 minutes for the first 40 moves, then 30 more minutes for the rest of the game, 30 seconds added from move 1 (the FIDE Chess Olympiad 2026 control) 150 min, standard under FIDE
G/30 d/5 US Chess notation: game in 30 minutes with a 5-second delay before each move 35 min by the US Chess “mm+ss” count

Increment or delay?

Increment and delay are the two ways a clock can give you time for each move. With an increment (Fischer), seconds are added after every move, so quick moves build a reserve. With a delay, the clock waits a few seconds before it counts down (simple or “US” delay) or gives back the time you used up to that limit (Bronstein delay); either way your time never rises above what you had at the start of the move. To watch both run side by side, and to see why Bronstein and simple delay always end a move on the same number, read Increment vs delay: Fischer, Bronstein and simple delay.

Try it on The Chess Timer

Pick a preset and the clock opens ready to start, with no account and nothing to install:

  • 3+2: blitz with a small increment, the FIDE World Blitz Championship control.
  • 5+3: the default preset, a comfortable blitz game.
  • 15+10: rapid, the FIDE World Rapid Championship control.

Choose Custom for a delay, a second stage, or different times for the two players.

Sources

All rules quoted above were checked against the primary documents on 2026-09-28: