Tournament Matches Calculator (Round-Robin, Knockout, Double Elimination)

What this tool does

A knockout needs one fewer match than there are teams, because every match sends exactly one team home and only the winner stays. Round-robin grows much faster, as t(t − 1) ÷ 2: 8 teams play 28 matches, 16 teams play 120. With an odd number of teams one team rests each round, so a round-robin takes t rounds instead of t − 1. When the team count is not a power of two, a knockout gives the difference as byes in the first round. In double elimination everyone but the champion loses twice, so there are 2t − 2 matches, or one more if the unbeaten finalist loses the first final and a decider is played.

Formula

round-robin = L · t(t − 1) ÷ 2 · knockout = t − 1 · rounds = ⌈log₂ t⌉ · byes = 2^⌈log₂ t⌉ − t · double elimination = 2t − 2 or 2t − 1

Variables

Worked example

Limitations

• The calculation runs at full precision and only the display is rounded. If you copy an intermediate value and retype it, small differences can appear.
• The default values are typical reference figures, not measurements of your situation. Replace them with your own data whenever you have it.