Increment vs Delay: Fischer, Bronstein & Simple Delay

Time controls · The mechanics · Updated 2026-08-07

Most digital chess clocks offer three ways of giving time back on each move: Fischer increment, Bronstein delay, and simple (US) delay. Clock menus rarely explain the difference, yet the three behave differently in exactly the moments that decide games: scrambles under ten seconds, long technical endgames, and any position where you need your clock to climb instead of fall.

Here is the short answer. Fischer increment adds a fixed number of seconds after every move you complete, and unused seconds accumulate, so your clock can rise above where it started. Bronstein delay also adds time after your move, but never more than you actually spent, so your clock can never rise. Simple delay just waits a few seconds before your main time starts counting down. Everything below is the exact math, side by side, plus which mode to pick and how to set it.

The three timing methods at a glance

All three methods solve the same problem: with a fixed budget and nothing coming back, every long game eventually collapses into a pure speed contest. Giving a few seconds back per move keeps late positions about chess instead of hand speed. One piece of notation first: a control written as X+Y, such as 3+2, means X minutes of base time per player plus Y seconds added per move. Whether those Y seconds arrive as increment or as delay is exactly the question this guide answers. For where each control sits among bullet, blitz, rapid, and classical, see chess time controls explained.

The third column is the entire practical difference. Under Fischer, fast moves are an investment: every move played in under Y seconds leaves your clock higher than before. Under either delay method, fast moves merely stop the bleeding. That single property changes how endgames and scrambles feel, as the worked examples below show.

Fischer increment: seconds that accumulate

Fischer increment adds Y seconds to your clock every time you complete a move, starting from move one. In a 3+2 game you begin with 180 seconds. Play your first move in 1 second and your clock ticks down to 179, then jumps to 181 the instant you press. You are already above your starting time. Keep moving faster than 2 seconds per move and your clock rises continuously.

The accumulation adds up to real thinking time. A 3+2 blitz game that lasts 60 of your moves feeds you 60 x 2 = 120 extra seconds, turning a 3-minute budget into 5 minutes of total thinking time. The effect scales with the control. FIDE's standard classical control is written 90+30: 90 minutes for the first 40 moves plus 30 minutes for the rest of the game, with a 30-second increment from move one. Over the first 40 moves the increment alone contributes 40 x 30 = 1,200 seconds, a full 20 extra minutes.

Strategically, increment means you are never completely dead on time. From 5 seconds in a drawn rook endgame, a stretch of instant, safe moves can rebuild your clock to a workable 20 or 30 seconds, enough to hold or convert on the merits of the position. That is why increment is the default for serious play: flagging still happens, but it punishes bad clock management rather than the mere existence of a long game.

Bronstein delay: added after your move, but capped

Bronstein delay also adds time after your move, with one restriction: you get back what you spent, up to a maximum of Y seconds. Spend 5 seconds on a move under Bronstein 2 and you get 2 back. Spend 1 second and you get exactly 1 back, not 2. The consequence is a hard ceiling: your clock can never rise above the level it showed before the move began.

Follow the arithmetic in a 3-minute game with a 2-second Bronstein delay. You start at 180 seconds. Think for 5 seconds on move one: the clock falls to 175, then refunds 2, landing on 177. Move in 1 second on move two: it falls to 176 and refunds only 1, returning to exactly 177. However fast you play, the best you can do is tread water.

The design is a deliberate compromise: every move gets a small free window, so you are not flagged simply for playing out a long game promptly, but nobody can bank time and enter the endgame on an inflated clock.

Simple (US) delay: a pause before the countdown

Simple delay, also called US delay, is the bluntest of the three. After your opponent presses, your clock waits Y seconds before the main time begins counting down. Nothing is ever added, and unused delay evaporates the moment you press. USCF commonly uses a 5-second delay, written d5, for regular time controls.

The math is a ratchet. With d5, a move played in 3 seconds costs you nothing, because you never exhausted the free window. A move played in 9 seconds costs you 4 seconds of main time, since the first 5 were free. Your displayed time only ever moves down, but every move starts with a grace period.

Worked example: four moves, three methods

The cleanest way to see all three at once is to run identical moves through each. The table uses a 3-minute base with 2 seconds of increment or delay and tracks time remaining after each press.

Two things stand out. First, only the Fischer column ever rises: move two took less than the 2-second increment, so the clock climbed from 2:57 to 2:58. Second, the Bronstein and simple delay columns match on every row, and that is no coincidence. Refund the smaller of the delay or the time you spent after the move, or grant the delay for free before the countdown: either way, a move only costs you the time beyond Y. The two delay methods are mathematically equivalent. What differs is presentation: under Bronstein your displayed time visibly drops during the free window and then jumps back, while under simple delay the display stands still until the window runs out. Some players find the frozen clock of simple delay calmer in a scramble; the arithmetic does not care.

Which method should you play?

• You want endgames decided by chess, not hand speed: pick Fischer increment. Banked seconds let a defender hold a fortress or a winner convert a technical position from almost nothing on the clock.
• You are preparing for a USCF over-the-board event: practice with a 5-second simple delay, because that is what the tournament clock will do. The rhythm of a frozen 5-second window feels different from an increment refund.
• You are preparing for FIDE-rated or online play: practice with Fischer increment. Standard controls at every speed, from 3+2 blitz to 90+30 classical, add seconds on every move.
• You want maximum pace pressure without pure sudden death: use a delay mode. Nothing banks, so the urgency never fades, yet no one loses time on moves played inside the window.
• You are timing a board game other than chess: any of the three works for alternating turns. See the board game timer guide for tournament Scrabble's 25 minutes per player and for Go's byo-yomi overtime, which is its own separate system of repeating periods.

Standard controls that use added seconds

Increment is baked into the standard controls at every speed. The common convention, aligned with FIDE, draws the category lines by base time: bullet is under 3 minutes per player, blitz is 10 minutes or less, rapid is more than 10 and under 60, and classical is 60 minutes or more. Notice how the added seconds grow with the base time: a 2-second increment matters enormously at bullet speeds and would be invisible in a classical game.

How to set each mode on your clock

1. Pick the base time: Decide the X in X+Y first and match it to the game you want: 3 or 5 minutes for blitz, 10 to 25 for rapid, 60 or more for a classical session.
2. Choose the mode: Select Fischer, Bronstein, or delay in the clock's settings. Many clocks list Bronstein and simple delay separately even though they cost identical time; pick whichever display you prefer to watch.
3. Set the seconds: Enter the Y value. Common pairings: 1 or 2 seconds for bullet and blitz, 5 or 10 for rapid, 30 for classical, and d5 if you are simulating USCF conditions.
4. Start the game correctly: Place the clock where the arbiter, or Black in casual play, decides, and have Black start White's clock to begin. Full etiquette, including the same-hand rule, is covered in how to use a chess clock.

Common mistakes and misconceptions

• Assuming increment starts late. Fischer increment applies from move one. In 90+30 you are earning 30 seconds from your very first move, not only after move 40.
• Thinking a rising clock is a glitch. Under Fischer, a clock climbing above its starting time is the mode working exactly as designed, because unused increment accumulates.
• Expecting delay to bank. Under d5, five instant moves in a row do not stash 25 seconds for later. Unused delay is gone the moment you press.
• Reading Bronstein's refund as a gain. The refund is capped at what you actually spent, so the clock can jump back up after a long think but can never exceed its previous ceiling.
• Forgetting the flag rules. If your time expires while your opponent has mating material, you lose on time; if they have only a lone king, the game is a draw, not a loss. Increment and delay scrambles make this rule come up often, so know it before you need it.

One clock, every mode. Chess Clock: Board Game Timer by Panda Taps puts Fischer increment, Bronstein delay, and simple delay behind one tap-to-switch interface on iPhone and iPad. Ready-made presets cover bullet, blitz, rapid, and classical along with board-game timing, per-player time odds handle handicaps, move counters track the game, and the flag indication is loud and unmistakable. It works fully offline, with no account and no ads. Download Chess Clock: Board Game Timer on the App Store.

Frequently asked questions

What is the difference between increment and delay in chess?

Increment adds a set number of seconds to your clock after every move, and unused seconds accumulate. Delay gives you a free window on each move but never adds to your total, so your clock can never rise. Fischer is the standard increment; Bronstein and simple delay are the two delay styles.

Can your clock go up during a chess game?

Yes, but only with Fischer increment. If you move in less time than the increment, the difference is banked, and a run of fast moves can lift your clock above where it started. Under Bronstein or simple delay the clock can never exceed its previous level.

What does d5 mean on a chess clock?

It means a 5-second simple delay: the clock waits 5 seconds before your main time starts counting down on each move. Nothing is added to your clock and unused delay does not carry over. USCF commonly uses d5 for regular time controls.

Are Bronstein delay and simple delay the same?

They leave you with exactly the same time after every move, so they are mathematically equivalent. The difference is presentation: Bronstein counts your time down and then refunds up to the delay after you move, while simple delay pauses before the countdown begins.

Keep reading

• Chess Time Controls Explained: Bullet, Blitz, Rapid & Classical
• How to Use a Chess Clock: Rules & Etiquette
• Using a Chess Clock as a Board Game Timer