Tournaments · Brackets
Tournament bracket size and byes calculator.
Enter the number of teams. See the bracket size, byes, rounds, and the games in single and double elimination.
Inputs
Bracket size
Enter 2 to 4,096 teams.
How many byes does a bracket need?
Round the number of teams n up to the next power of two to get the bracket size, then subtract: byes = 2k − n. The first round has n − 2k−1 games and the rest of the bracket is a clean halving to the final. The number of rounds is k.
Games. Single elimination always has n − 1 games. In double elimination a team is out after two losses, so there are 2n − 2 games if the winner never lost, or 2n − 1 if the winner lost once and the final is played twice (the bracket reset). 8 teams: 7 games single, 14 or 15 double.
Worked example. 12 teams: bracket of 16, 4 byes, 4 rounds, 4 games in round 1, 11 games single elimination, 22 or 23 double. 17 teams is the awkward case: the bracket jumps to 32, so there are 15 byes and only 1 game in round 1.
To see who plays whom, use the single elimination bracket generator.
Frequently asked questions
How do you calculate byes in a tournament bracket?
Byes = the next power of two at or above the number of teams, minus the number of teams. 10 teams: 16 − 10 = 6 byes.
How many games in a double elimination tournament?
2n − 2 if the champion is undefeated, or 2n − 1 if the champion lost once and the final is played twice. For 8 teams that is 14 or 15.
How many rounds are in a single elimination bracket?
The base-2 logarithm of the bracket size: 3 rounds for 5 to 8 teams, 4 for 9 to 16, 5 for 17 to 32.
Why does the bracket reset exist?
In double elimination the finalist from the losers bracket has one loss and the winners-bracket finalist has none. Because everyone is eligible until their second loss, the losers-bracket finalist must beat the other team twice, so a second final is played if the first goes to the losers-bracket team.
Sources
Checked
Wikipedia states that a double-elimination tournament has "either 2n − 2 or 2n − 1 games depending on whether or not the winner was undefeated" and describes the bracket reset. Single elimination counts and byes are arithmetic from the one-loss-out rule and are unit-tested here. Runs entirely in your browser. Nothing you type is sent or stored.
Scope
A planning aid for casual and club events. Check your own league or federation rules for official formats, seeding, tiebreakers and pairings.