A single round robin has one matchup for every possible pair of participants. The formula is n x (n - 1) / 2, where n is the number of teams or players.
Round robin game counts
- 4 teams: 6 games
- 5 teams: 10 games
- 6 teams: 15 games
- 7 teams: 21 games
- 8 teams: 28 games
- 10 teams: 45 games
- 12 teams: 66 games
Why the formula works
Each participant can play n - 1 opponents. Multiplying n by n - 1 counts every matchup twice, once from each participant's side. Dividing by 2 leaves the actual number of games.
Rounds are different from games
Games are total matchups. Rounds are the blocks of time needed to run them. Six teams need 15 games across 5 rounds. Seven teams need 21 games across 7 rounds because one team has a bye each round.
Estimate your event time
First calculate matches per round, then divide by courts. If eight teams create four matches per round and you have two courts, each round needs two match slots. With 25-minute matches, each round needs about 50 minutes before breaks.
When the count is too high
If the number of games is too large, use pools, shorten match length, add courts, or switch to a bracket. Do not force a full round robin if the schedule becomes too long for the venue.
Quick answers
How many games are in an 8-team round robin? 28 games.
How many games are in a 10-team round robin? 45 games.
Does a double round robin double the games? Yes. Each pair plays twice, so an 8-team double round robin has 56 games.