Random Tournament Bracket
Single-elimination bracket from a shuffled seed.
Built and maintained by Paul Clark, Redmoon Software · Last checked
The Random Tournament Bracket builds a complete single-elimination bracket from a shuffled, random seeding of your entrants. It's handy for game nights, sports leagues, esports, or office competitions where you want a fair draw nobody can argue with. Enter your players and get an instant first round, with byes handled automatically when the field isn't a power of two.
Enter. Add your entrants, one name per line.
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Click Build bracket to see a result.
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How it works
- Enter. Add your entrants, one name per line.
- Build. Click Build bracket to shuffle the seeds and lay out the matchups.
- Review. Check the first-round pairings and any randomly assigned byes.
- Rebuild. Build again for a different random draw if you'd like a do-over.
About the Random Tournament Bracket
Byes, and who gets one
A knockout bracket needs a power-of-two field, so the tool rounds your entry list up to the next one — five entrants become eight, nine become sixteen — and fills the gap with byes. A bye is a free pass into round two.
The order matters here and it is fair by construction: entrants are shuffled first, and the byes are appended afterwards. So whoever ends up with a bye is decided by the same random draw that decides everything else, rather than by where they appeared in your list. Nobody gets a free pass for having been typed first.
The corollary is worth planning for: nine entrants means seven byes, and a first round where most matches are walkovers. If that looks silly, either find more entrants or run a different format.
It generates round one only
What you get is the opening set of pairings, not a full tournament tree — there is nothing to record results into and nothing that advances winners. That is a deliberate limit rather than a missing feature: the pairings for round two depend on who wins, which the tool cannot know.
In practice most people take the round-one list, play it, and then paste the winners back in for the next round. Doing that gives you a genuinely random second round, which is a slightly different tournament from a traditional fixed bracket where the path is known in advance — decide which one you are running before the first match, because the difference matters to anyone planning ahead.
Seeding, or the deliberate lack of it
There is no seeding. A proper seeded bracket keeps the two strongest entrants apart until the final; a random draw can easily pair them in round one. For a casual tournament that unpredictability is usually the appeal, and for anything competitive it is a genuine flaw.
If you need seeding, the honest approach is to build the bracket by hand and use this tool only for the parts that should be random. Setting a Seed here makes the draw reproducible — publish the entry list and the seed before you run it and the bracket becomes something anyone can verify, which is worth doing whenever there is a prize.
Frequently asked questions
What happens if I don't have a power-of-two number of entrants?
Some entrants get a first-round bye, randomly assigned, so the bracket fills out to the next power of two.
How random is the seeding?
Entrants are shuffled with your browser's Web Crypto API, giving a cryptographically sound, unbiased draw every time.
Does it support single or double elimination?
This tool generates a single-elimination bracket, where one loss eliminates an entrant.
Is my list of entrants uploaded anywhere?
No. Everything runs locally in your browser and works offline, so your entrants are never sent to a server.
Related randomizers
Further reading
- The math behind a weighted fantasy draft lottery
Turning on weighted lottery mode doesn't give last year's worst team the first pick — it gives them better odds at it. Here's exactly how the weighting works, what the probabilities look like for a typical league, and how a seed lets you prove the draw was fair after the fact.
- Setting up a fair fantasy draft order before your league fights about it
Flat random or weighted lottery? How to pick a fantasy draft order method your league will respect, plus how to run an animated, screen-shared reveal on draft night.
- Proving a shuffle wasn't rigged: seeded shuffles and the duplicate trap
Anyone can claim a shuffle was fair after the fact. A seeded shuffle lets you prove it — and the copy-paste duplicate that quietly stacks the odds is the other thing worth catching before you hit Randomize.
- Eliminate one at a time until a single survivor is left
A bracket pairs things off; an elimination picker just keeps knocking one out until one remains. Here's how a round-by-round survivor draw works, why the elimination order is half the fun, and when to seed it so the result is provable.
- Seeding a tournament bracket fairly (and why byes are trickier than they look)
Throwing names into a single-elimination bracket sounds simple until you hit an odd number of players, byes that hand someone a free win, or a seeding that pits your two best players in round one. Here's how to do it right.