Tournament Organizer
Exact match counts for single elimination, double elimination and round robin, plus a seeded bracket — so you know what you are committing to.
Pick a format
| Format | Matches | Rounds | Time | Notes |
|---|
The match counts are exact
Single elimination is always n − 1 matches, byes or not. Every match eliminates exactly one entrant, and everybody except the winner gets eliminated, so the count cannot be anything else. It is one of the few tidy facts in tournament design.
Round robin is n(n − 1)/2, which grows as the square of the field. Six players is 15 matches, nine is 36, thirteen is 78 — which is exactly why round robin stops being an afternoon somewhere around ten people, and why the decision is worth making before everyone arrives rather than after.
Things worth knowing
- Single elimination is always n − 1 matches, whatever the byes. Every match eliminates exactly one entrant and everyone but the winner gets eliminated, so the count cannot be anything else.
- Round robin match count grows as the SQUARE of the field. Six players is 15 matches, nine is 36, thirteen is 78 — which is why it stops being an afternoon somewhere around ten.
- Byes go to the top seeds. That is the entire reward for seeding well, and handing them out at random defeats the purpose of seeding at all.
- With eight or fewer people and time to spare, round robin is almost always the better party. Everybody plays the same number of games and nobody drives home after nine minutes.
- Double elimination roughly doubles the matches and removes the worst feature of a knockout — that one bad game against the eventual winner ends your day.
How to use
- Enter the number of entrants.
- Compare the formats by match count and time.
- Choose seeding and byes deliberately.
- Publish the format and tiebreakers before entries close.
Frequently asked questions
How many matches does each format need?
Single elimination needs one fewer than the number of entrants, since every match eliminates exactly one. Double elimination needs roughly twice that. A round robin needs every pairing, which grows as the square of the field — sixteen players is 120 matches, which is why it does not scale.
Which format should I choose?
Single elimination when time is short and a quick result matters. Round robin when fairness matters and the field is small, since everyone plays everyone. Double elimination is the common compromise, giving each entrant a second chance without the full cost of a round robin.
Why does single elimination get criticised?
Because one bad match ends a run regardless of overall standard, and the outcome depends heavily on the draw. It is the least reliable format at identifying the strongest entrant, and it is used anyway because it is fast and dramatic.
How do byes work?
When the field is not a power of two, some entrants skip the first round. Byes conventionally go to the top seeds, which is a real advantage — fewer matches and more rest. Distributing them evenly through the bracket is what stops a section being lopsided.
Why does seeding matter?
Because it keeps the strongest entrants apart until later rounds, which produces better matches at the end. Random draws are more impartial and frequently produce a strong pairing in round one, eliminating a contender early. Both are defensible and the choice should be announced in advance.
What should be agreed before entries close?
The format, the seeding basis, how byes are allocated, tiebreakers for round robin, and what happens if someone withdraws. Deciding any of those after the draw is how tournaments generate arguments, because by then everyone can see who benefits.
🔒 This tool runs entirely in your browser. Nothing you enter is uploaded, logged, or stored.