Picking a format is the first decision any organizer makes. The short answer: round-robin for small groups, Swiss for everything else.

Round-robin

In a round-robin every player meets every other player once. It is the fairest format because the winner has beaten (or drawn) the whole field.

  • Rounds needed: players minus 1 (an even number of players), so 6 players need 5 rounds and 8 players need 7.
  • Best for: 4 to 10 players, invitational events, closed norm tournaments.
  • Drawback: the number of rounds grows quickly, so it does not scale to large events.

Swiss system

In a Swiss, players with similar scores are paired each round, and nobody is eliminated. A tournament of 100 players can finish in just 7 or 9 rounds.

  • Rounds needed: roughly log2 of the number of players, rounded up, plus one or two if you want a clear winner.
  • Best for: 10 or more players, open events, school and club championships.
  • Rules: no two players meet twice, and colours are balanced as far as possible.

Rules of thumb

Players Suggested format
4 to 8 Round-robin (or double round-robin for 4)
9 to 16 Swiss, 5 rounds
17 to 64 Swiss, 6 to 7 rounds
65 and up Swiss, 7 to 9 rounds

Tie-breaks

When players finish on the same score, tie-breaks decide the order. Buchholz (the sum of your opponents' scores) is the most common in Swiss events; Sonneborn-Berger is preferred in round-robins because it rewards beating strong opponents.

Ready to run it? Our free tournament manager creates both formats, calculates the tie-breaks and gives you a shareable live results page.