12 player Swiss tournament
12 players, 4 rounds, and nobody knocked out. Each round pairs players on the same record, and the next round draws itself the moment the last result of the previous one goes in.
- Rounds
- 4
- The fewest that can still leave one team unbeaten.
- Matches
- 28
- Including semi-finals and a third-place match for the top four.
- Matches each
- 4
- Nobody is knocked out — everyone plays every round.
- Roughly how long
- 5 h 45 min on 2 courts
- Allowing 25 minutes a match, courts running in parallel.
Free, and there is no account to make first. About a minute to the QR code.
Why 4 rounds
ceil(log2(12)) is 4 — the fewest rounds that can still leave exactly one player unbeaten, which is the standard answer to "how long should a Swiss be". Whistle.day floors it at three, because a two-round Swiss has not sorted anything out.
You can run it longer for a fuller table. Against a field of 12 there are 11 possible opponents, so past that the draw would have nothing fresh left; well before then it will start having to repeat a meeting, and it tells you when it does.
Nobody is knocked out
Everybody plays all 4 rounds. That is the reason to run a Swiss rather than a knockout for a field this size: 12 players in a straight bracket means half of them have finished by the end of round one, and a Swiss gives every one of them the same day.
12 is even, so every round pairs the whole field with nobody sitting out.
And then a playoff, if you want one
The default carries the top four off the Swiss table into semi-finals and a third-place match, which is what the match total above includes. Ending on the table alone works too — it is a stage setting rather than a different format.
Common questions
How many rounds for 12 players?
4. That is ceil(log2(12)), the fewest that can leave one player unbeaten.
Do I have to pair each round myself?
No. Finishing a round is what draws the next one, from the table as it stood at that moment. There is a manual pairing endpoint but it is the repair path.
Can the same two players meet twice?
The pairing avoids it. On a small field over a long tournament it can run out of fresh opponents, in which case it repeats a meeting and says so.