Brackets are powers of 2: 2, 4, 8, 16, 32, 64. That's not arbitrary — it's the only structure where every round perfectly halves the field. But your real-world player count is rarely a clean power of 2. Here's how brackets handle that, and how to think about sizing your tournament.
Why powers of 2?
A bracket is a binary tree. Each match takes two players and produces one winner. Round 1 needs every player matched up with someone — meaning the player count must be even. Round 2 is half of round 1. Round 3 is half of round 2. The cleanest way for this to work is to start with a number that halves all the way to 1: 2, 4, 8, 16, 32, 64, 128.
If you start with an odd number, or any number that's not a power of 2, you have to fudge the first round somehow. The fudging is called byes.
How byes work
If you have 7 players, the bracket rounds up to 8 (the next power of 2). One slot in round 1 is empty. The player paired with that empty slot gets a "bye" — an automatic win, no opponent. They advance straight to round 2.
Byes always go to the top seeds. With 7 players in an 8-bracket, the #1 seed gets the bye. With 13 players in a 16-bracket, the top 3 seeds get byes.
Bracket sizes by player count
| PLAYERS | BRACKET SIZE | BYES | VERDICT |
|---|---|---|---|
| 2 | 2 | 0 | Just play. |
| 3 | 4 | 1 | Fine — 25% byes is OK. |
| 4 | 4 | 0 | Perfect. |
| 5 | 8 | 3 | ⚠ 37% byes — find one more player. |
| 6 | 8 | 2 | OK — 25% byes. |
| 7 | 8 | 1 | Good — only 12% byes. |
| 8 | 8 | 0 | Perfect. |
| 9-12 | 16 | 4-7 | ⚠ Too many byes. Either find more players or run two 8-brackets. |
| 13-15 | 16 | 1-3 | Good — under 20% byes. |
| 16 | 16 | 0 | Perfect. |
| 17-24 | 32 | 8-15 | ⚠ Painful. Run multiple 16-brackets if possible. |
| 25-32 | 32 | 0-7 | OK — under 22% byes. |
The 40% bye rule
BTop flags any tournament where byes exceed ~40% of the bracket. Why? Because a bracket where half the players don't actually play in round 1 isn't really a tournament — it's a glorified seeding exercise. Better options:
- Find one more player. Even a casual walk-up can save your bracket. 5 players → 6 players takes you from 37% byes to 25%.
- Run two smaller brackets. 12 players? Don't run one 16-bracket with 4 byes; run two 8-brackets and pit the winners against each other in a finals match. More fun, more matches per player, no byes.
- Use double elim. Double elim's losers bracket structure handles byes better — the byes are concentrated in early rounds and don't impact the finals.
How seeding interacts with bracket size
BTop assigns seeds based on player insertion order at draw time (it's actually a randomized shuffle in production, but you can think of it as random). Top seeds get byes. So the player who happens to draw seed #1 gets a head start — they skip a round.
For casual bar tournaments, this is fine — random seed = random byes. For league nights with skill rankings, you might want to enter players in skill order so the strongest ones get the byes. BTop doesn't enforce this; it's up to you what order to add players.
Match counts by bracket size
Useful for estimating how long the tournament will take:
- 4 players · 3 matches in single elim, 6 in double elim
- 8 players · 7 matches single, 14 double
- 16 players · 15 matches single, 30 double
- 32 players · 31 matches single, 62 double
- 64 players · 63 matches single, 126 double
If a match takes 8 minutes (race-to-2 pool, average), an 8-player single-elim on one table takes 56 minutes. Add a second table and you're at ~30 minutes. Add a third and the bottleneck becomes the final, not the round volume.
Practical recommendations
4-8 players: single elim, race-to-2, one table. 30-60 minutes.
9-16 players: if you can get to 16, run a single 16-bracket. If you can't, run two 8-brackets feeding a final.
17-32 players: aim for 32. If you have 24, run a 32-bracket and let the byes go to the top 8 seeds — that's still under 25% byes which is workable.
33+: you're at scale. Multi-table is essential. Talk to us — we want to learn from your night.