Round Robin Tournament Calculator
How many matches a round-robin needs, how many rounds it takes, and how long the whole thing will run — for any number of teams.
In a single round robin every team plays every other once, so the number of matches is n(n − 1) ÷ 2 — the handshake formula.
How the round robin tournament calculator works
In a single round robin every team plays every other once, so the number of matches is n(n − 1) ÷ 2 — the handshake formula. It grows quadratically, which is the thing organisers underestimate: doubling from 8 teams to 16 takes the schedule from 28 matches to 120, more than four times as many.
The number of rounds is n − 1 for an even count, or n for an odd one, where each round has one team sitting out on a bye. With an odd number of teams somebody is always idle, which is why organisers so often add a dummy entry to make the count even.
Formula: matches = n(n − 1) ÷ 2; rounds = n − 1 (even) or n (odd)
Worked examples
| Inputs | Total matches | Note |
|---|---|---|
| 8 teams, single round robin | 28 | 28 matches over 7 rounds |
| 16 teams | 120 | 120 matches — four times an 8-team draw |
| 10 teams, home and away | 90 | 90 matches over 18 rounds |
FAQFrequently asked questions
How many matches in a round robin?
n(n − 1) ÷ 2 — the same as counting handshakes in a room. Eight teams need 28 matches.
How many rounds does it take?
One fewer than the number of teams if that number is even, and equal to it if odd, because someone sits out each round.
Why does it grow so fast?
Because matches grow with the square of the entries. Doubling from 8 to 16 teams takes 28 matches to 120.
What if I have an odd number of teams?
One team has a bye each round. Organisers often add a dummy entry to make the count even and keep every round full.
When should I use groups instead?
Once a single round robin passes about 60 matches, groups feeding a knockout stage usually fit the available time far better.
Where these figures come from
- World Handicap System — Rules of Handicapping — the score differential and handicap index formula
- International Cricket Council — Playing Conditions — over structure and run-rate definitions
- Major League Baseball — Official Rules — the published definitions for baseball statistics
Last checked: September 2026. Formulas follow the governing bodies where one publishes them — the World Handicap System for golf, the ICC playing conditions for cricket run rates.