Work out knockout rounds instantly with clear inputs, formula shown and shareable results.
The number of rounds is the base-two logarithm of the entry count rounded up, and every knockout needs entrants minus one ties regardless of how they are seeded. Doubling the field adds only one round, which is why a 64 team draw takes six rounds and a 128 team draw takes seven.
Rounds
rounds = ceiling(log2(entrants))
Games
games = (entrants - 1) x 2 for two-legged ties
rounds = ceiling(log2(entrants)). The number of rounds is the base-two logarithm of the entry count rounded up, and every knockout needs entrants minus one ties regardless of how they are seeded.
Doubling the field adds only one round, which is why a 64 team draw takes six rounds and a 128 team draw takes seven.
Enter number of entrants, two-legged ties. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.