The Fischer increment, explained

Why the increment exists

Before increments, every sudden-death time control ended the same way: whoever was short on time started blitzing out moves, pieces flew, and games were won on the clock rather than on the board. Bobby Fischer found this an artistic failure of chess and designed a clock that gives a small time bonus for every completed move.

The effect is profound. With even a 2-second increment you can always gain time by moving quickly in a simple position, so a technically winning endgame can actually be converted instead of being lost on time. That is why nearly every serious event today — including the FIDE World Championship — uses a Fischer increment.

Reading a time control like 5+3 or 15+10

Chess time controls are written as base + increment:

The increment is credited for every move, including the first one, and there is no cap: if you move faster than the increment, your clock actually grows.

Increment before or after the move?

There are two ways a clock can apply the bonus, and good clocks (and Chess Clock) support both:

• Fischer after (standard): the seconds are added when you complete your move and press the clock. This is what almost all online platforms and modern events use.
• Fischer before (FIDE style on some clocks): the seconds are added to your clock the moment your turn begins. The practical difference is subtle: with "before", you can never flag while still having the increment available for your current move; with "after", finishing your move is what earns the bonus.

For casual play the difference rarely matters — but if you are simulating a specific tournament's conditions, it is worth matching their setting.

Fischer vs. Bronstein vs. delay

The Fischer increment is often confused with two related systems:

• Bronstein delay refunds the time you spent thinking, up to the bonus amount — your clock can never grow. A 5-second Bronstein and a 5-second US delay are mathematically equivalent, just displayed differently.
• US delay (simple delay) waits a fixed number of seconds before your main time starts ticking. Popular in USCF events.

Rule of thumb: Fischer rewards fast play with a growing clock; Bronstein and delay only protect you from losing time on instant moves. Our guide on Bronstein vs. delay covers the details.

Setting up a Fischer increment in the app

In Chess Clock, every preset with a "+" already uses a Fischer increment — 3+2 and 5+3 Blitz, 10+5 and 15+10 Rapid, 90+30 Classical, and the FIDE tournament control. To build your own, create a custom time control, choose base time and increment, and pick Fischer (after move) or Fischer (before move) as the mode. You can even give each player a different increment as a handicap.