Every organiser eventually faces the same problem: registration closes with 11 teams, or 23, or 37, and the bracket only works cleanly with 8, 16, 32 or 64. The answer is the BYE, a free advance to the next round for teams that have no opponent. This guide explains how many BYEs you need, who should get them, and what changes in double elimination and Swiss formats.
Why brackets need a power of two
A single elimination bracket halves the field every round. Sixteen teams become eight, then four, then two, then one champion. That only works if the number of teams in the first full round is a power of two (2, 4, 8, 16, 32, 64, 128). With any other number, at some point a team would have no one to play.
BYEs solve that by filling the empty slots in round one. A team with a BYE advances automatically, and from round two onwards the bracket halves cleanly.
The BYE formula
To work out how many BYEs you need:
- Find the smallest power of two that is greater than or equal to your team count. Call it the bracket size.
- Subtract your team count from the bracket size. The result is the number of BYEs.
With 11 teams, the next power of two is 16, so you need 16 − 11 = 5 BYEs. Five teams skip round one, and the remaining six teams play three first-round matches. After round one there are 5 + 3 = 8 teams left, a clean power of two.
BYE lookup table
| Teams | Bracket size | BYEs | Round-one matches | Total matches |
|---|---|---|---|---|
| 3 | 4 | 1 | 1 | 2 |
| 5 | 8 | 3 | 1 | 4 |
| 6 | 8 | 2 | 2 | 5 |
| 7 | 8 | 1 | 3 | 6 |
| 9 | 16 | 7 | 1 | 8 |
| 10 | 16 | 6 | 2 | 9 |
| 11 | 16 | 5 | 3 | 10 |
| 12 | 16 | 4 | 4 | 11 |
| 13 | 16 | 3 | 5 | 12 |
| 14 | 16 | 2 | 6 | 13 |
| 15 | 16 | 1 | 7 | 14 |
| 20 | 32 | 12 | 4 | 19 |
| 24 | 32 | 8 | 8 | 23 |
| 28 | 32 | 4 | 12 | 27 |
| 40 | 64 | 24 | 8 | 39 |
| 48 | 64 | 16 | 16 | 47 |
Two patterns are worth remembering. First, a single elimination bracket always has exactly one fewer match than it has teams, because every match eliminates one team and every team except the champion is eliminated once. BYEs do not change that. Second, the number of round-one matches is always the team count minus the bracket size divided by two, which is why 9 teams in a 16 bracket produce just one opening match.
Who should get the BYEs
BYEs go to the highest seeds, in order. With five BYEs, seeds 1 through 5 advance automatically. This is the convention in virtually every competitive circuit, and for good reason: a BYE is a reward for being ranked highly, in the same way that facing the lowest seed in round one is a reward.
There are two situations where organisers sometimes deviate:
- Casual events with random seeding. If seeding is random, BYEs are effectively random too. That is acceptable as long as the rules say so upfront.
- Late withdrawals. If a team withdraws after the bracket is published, its opponent receives a walkover rather than the bracket being redrawn. That is technically a forfeit win, not a BYE, and it should be recorded that way.
Where the BYEs sit in the bracket
A seeded bracket places each BYE opposite the top seed it belongs to. In a 16-slot bracket with 13 teams, seeds 14, 15 and 16 are empty, so the matches that would have been 1 v 16, 2 v 15 and 3 v 14 become BYEs for seeds 1, 2 and 3. That keeps the BYEs spread across both halves of the bracket instead of clustering them, which matters because a cluster of BYEs in one half makes that half far easier.
Are BYEs an unfair advantage?
Partly, yes, and that is intended. A team with a BYE plays one fewer match, so it arrives at round two fresher and with less chance of an upset. Some players argue that BYE teams arrive “cold” while their opponents are warmed up. In practice, for esports, the rest advantage and the removed upset risk outweigh any warm-up effect.
If you want to minimise BYEs, you have three options:
- Cap registration at a power of two and run a waitlist.
- Run a play-in round for the lowest seeds only. With 18 teams, seeds 15 to 18 play two play-in matches to fill a 16-team bracket.
- Use a different format. Round robin and Swiss handle any team count without needing a power of two.
BYEs in double elimination
Double elimination uses the same BYE count in the upper bracket. The lower bracket then inherits empty slots too, because the teams that had BYEs did not lose a round-one match to drop down. Good generators collapse those empty lower-bracket slots automatically so no team sits waiting for a match that will never happen. If you build a double elimination bracket by hand with an awkward team count, this is where most errors creep in.
BYEs in Swiss and round robin
In a Swiss tournament with an odd number of teams, one team receives a BYE each round. The usual rule is that the BYE goes to the lowest-ranked team that has not yet had one, and it counts as a win (sometimes worth the full match points, sometimes a draw’s worth, depending on your rules). No team should receive more than one BYE per event.
In a round robin with an odd number of teams, a “rest” slot rotates through the schedule, so every team sits out exactly one round. The round robin guide shows how the rotation works.
The short version
Round your team count up to the next power of two, subtract, and that is your BYE count. Give them to the top seeds, spread across both halves of the bracket. Or skip the maths entirely: paste any number of teams into the generator and it places the BYEs for you.