Chess time controls explained

The second number is seconds added every move. That one sentence answers most of it; the rest is where the category names come from and which pool to actually pick.

What the two numbers mean

5+3 means five minutes each, plus three seconds added to your clock every time you move. The first number is minutes on the clock at the start. The second is seconds of increment. That is the whole notation, and once you have it, 3+2, 10+5 and 15+10 all read themselves.

A control written 5+0 has no increment: five minutes is all you will ever have, and if it runs out you lose however good the position is.

Increment and delay are not the same thing

They both stop you losing on time in a position you are winning, and they do it differently.

Increment adds the seconds to your clock after you move, and they stay there. Move quickly for twenty moves in a 5+3 game and you can finish with more time than you started with. This is what is used here and on most online chess.

Delay waits before your clock starts running. In a game with a three-second delay, your clock does not begin counting down until three seconds have passed — but you cannot bank the ones you did not use. Your time can only go down. Delay is commoner in American over-the-board tournaments than online.

The practical difference: with increment you can build a cushion and a long endgame is genuinely playable. With delay you cannot, and a long endgame stays a scramble.

Bullet, blitz, rapid, classical: where the lines are

The names are not about the first number on its own, which is why 3+2 is blitz and 2+1 is bullet even though the base times are close. What is classified is an estimate of how long the game will actually last: the base time plus forty moves' worth of increment.

The boundaries, recovered by walking that estimate upward through the app’s own classifier until the answer changes. These are Lichess’s thresholds, kept deliberately: players already know what “blitz” means and would read a better-chosen split as simply wrong.
Category	Estimated length
Bullet	under 179 seconds
Blitz	179 to 478 seconds
Rapid	479 to 1498 seconds
Classical	1499 seconds and up

Worked once: a 3+2 game estimates at 3 × 60 + 40 × 2 = 260 seconds, which is over the 179-second bullet line, so it is blitz. A 2+1 estimates at 160, which is under it.

The pools here

Every time control Reflex Chess offers, straight out of public/app/timecontrol.js. “Estimated length” is the figure the category is decided on. The default is **5+0**.
Control	Clock	Increment	Category	Est. length
1+0	1 min	none	bullet	60 s
2+1	2 min	1s	bullet	160 s
3+0	3 min	none	blitz	180 s
3+2	3 min	2s	blitz	260 s
5+0	5 min	none	blitz	300 s
5+3	5 min	3s	blitz	420 s
10+0	10 min	none	rapid	600 s
10+5	10 min	5s	rapid	800 s
15+10	15 min	10s	rapid	1300 s
30+0	30 min	none	classical	1800 s
30+20	30 min	20s	classical	2600 s

Which one to pick

If you are choosing a control to send a friend, the honest advice is to go one step slower than you think. Bullet and blitz are enormous fun and they train almost nothing, because there is no time in them to calculate anything you cannot already see. A rapid game with increment — 10+5 or 15+10 — is where you can actually think, and it is where a mistake teaches you something instead of just costing you.

An increment of any size changes the ending of a game more than the base time does. In 5+0 a won endgame can be lost to the clock alone. In 5+3 it usually cannot.

The clock changes your opponent too

Something specific to playing a computer opponent, and it is why these pools are not just a menu. Nobody calculates four moves deep with two seconds left, and an opponent who did would not read as a person, so how far ahead your opponent is allowed to look is capped by the speed of the pool:

The search cap by category, from public/app/timecontrol.js. It is a cap, not a separate strength curve: a strong opponent in bullet plays shallower, not like a weak one.
Category	Look-ahead cap
Bullet	2 ply
Blitz	3 ply
Rapid	4 ply
Classical	5 ply

How the opponent is weakened covers the rest of it, including the part that is not search depth at all.

Pick a pool and play11 controls from 1+0 to 30+20, on a real clock, against an opponent at your rating. Or send the link to a friend and let them pick.Open Reflex Chess

What does 5+3 mean in chess?

Five minutes on the clock for each player, plus three seconds added to your own clock every time you move. The added seconds accumulate, so moving quickly early can leave you with more time than you started with.

What is the difference between increment and delay?

Increment adds seconds to your clock after each move and you keep them. Delay waits a fixed number of seconds before your clock starts running, and any of that time you do not use is gone. Increment lets you build a cushion; delay never does.

Is 5+0 blitz or rapid?

Blitz. The category is decided on the base time plus forty moves of increment, so 5+0 estimates at 300 seconds, which is inside the blitz band of 179 to 478.

What time control should a beginner play?

Rapid with increment, 10+5 or 15+10. Fast chess is enjoyable and trains almost nothing, because there is no time in it to work out anything you cannot already see.