🏆 Tournament Bracket Size Calculator

Enter the number of participants or teams to calculate the single-elimination bracket size, number of byes, and total rounds needed.

Number of Participants

Rounding up to the next power of two

A single-elimination bracket only works when the field halves cleanly, so the size is the next power of two at or above your entry count, and the gap is filled with byes:

bracket size = 2 ^ ceil(log2(entrants))
byes         = bracket size - entrants
round 1 matches = (entrants - byes) / 2
rounds       = log2(bracket size)

With 13 entrants the bracket is 16, leaving 3 byes. Ten players are left to pair off, so round one is 5 matches; the 5 winners join the 3 byes to make 8, and the draw runs 8, 4, 2, 1 - four rounds in all. The number of matches never depends on the byes: every match eliminates exactly one competitor and one survives, so a 13-entrant event is always 12 matches.

Seeding the byes

Byes go to the top seeds. Seed 1 down to seed 3 sit out the first round in the example. Handing them out at random is the usual way a bracket ends up with two strong players meeting in round two.
Spread them across the draw rather than clustering them in one quarter.
Power-of-two fields need none. 8, 16, 32 and 64 come back with zero byes and every entrant playing in round one.

This is single elimination only, for 2 to 1024 entrants. Double elimination roughly doubles the schedule to 2n - 1 matches because the field runs a losers bracket alongside, and round robin is n(n - 1) / 2 - 12 teams playing everyone once is 66 games, not 11.

Frequently asked questions

How many byes do I need for 13 teams?

Three. The nearest bracket above 13 is 16, and 16 - 13 = 3, so three teams advance to round two without playing.

How many games are in a single elimination tournament?

One fewer than the number of entrants. Twenty-four teams play 23 games, however the byes fall, because each game knocks out one team.

What is a bye in a tournament bracket?

A free pass through the first round, given when the field is not a power of two. It is a scheduling device rather than a reward, though the seeds who get one do bank a rest.