How a single elimination bracket works

1. What single elimination means

In single elimination one loss ends it. Wikipedia's article on the format puts it as "the loser of a match-up is immediately eliminated from the tournament". There is no losers' bracket and no points to add up, so every single match removes exactly one contender.

That makes the arithmetic simple. With thirty two options, thirty one have to be eliminated before one is left, and each match eliminates one, so there are exactly thirty one matches. Whatever your option count is, the number of matches is that count minus one. That line is not a sentence from the article, it falls out of the structure, and this page's own test checks it for every count from two to sixty four.

2. The basic rules: bracket size and byes

A bracket pairs options two at a time, and the winners have to pair up two at a time again. For that to work all the way down, the starting field has to be a power of two. So the bracket size is the smallest power of two that is at least as large as your option count. Sixteen and thirty two are the familiar numbers because they already are powers of two, which leaves no empty slots.

With twenty options the bracket size is thirty two and twelve slots sit empty. An option paired with an empty slot skips its first match and moves up. That is a bye, and the same article describes the spot: "If some competitors get a bye, the round at which they enter may be named the first round". This page writes out how many byes there are. It does not hide the fact that some options advanced without playing.

3. The rules inside this page

The order is shuffled once, at the start. Reshuffling on every tap would make the screen shift under you and lose the pairing you were just looking at. Because the shuffle happens once, undo is exact: it puts you back on the previous match, and the same pair reappears in the same places.

Byes go to the options nearer the front of the list, the same slot where a standard bracket hands byes to the top seeds. Since that front and back is the order after shuffling, who gets a bye differs from run to run.

Round names come from how many options entered that round. Sixteen entering makes it the round of sixteen, four makes it the semifinal, two makes it the final. The first round is named by the bracket size even when it has byes, so the number actually playing is smaller, and that difference is the bye count.

A bracket you build is not stored on a server. The question and the options are written into the address itself, and the browser that opens the link unpacks them into the same bracket. So we do not know who built what, and if you want it gone you throw the link away. There is no copy left behind.

The brackets shipped with the page carry no names of people and no photographs. They use dictionary words only: dishes, colors, countries. The page does not handle images at all, so there is nowhere to upload a picture.

4. Building your own

Write one option per line. Blank lines are dropped, and if the same word appears twice the later one is dropped, because two identical options would eventually face themselves in a final.

Sixteen or thirty two options finish cleanly with no byes. An awkward count like twenty works too, it just means a few options skip their first match. Too many becomes a slog in the other direction: thirty two options take thirty one taps, and sixty four take sixty three.

The question holds sixty characters and each option forty. That is what fits in one address and still reads inside a button. Longer text is cut, so a long explanation belongs in the question, kept short.

5. A little deeper

Single elimination is fast but it does not rank things accurately. If your second favourite meets your favourite in the first round it is gone right there, and whatever reaches the final may simply have drawn easier pairings. That is why the one that lost the final is not your number two, and why this page labels that slot as the one that lost the final rather than as runner up.

Playing every option against every other one would rank them better, but thirty two options mean four hundred ninety six matches against thirty one in single elimination. If the point is to narrow a choice quickly, single elimination is the right tool. If the point is a full ranking table, look for a different format.

Getting a different winner on a second run is information too: it separates the options that only survive on favourable pairings from the ones that keep coming through. If the same option keeps winning across several runs, that is probably your answer.

6. Where people get stuck

If a link you received says the bracket could not be read, the address was usually cut short. Messengers and mail clients sometimes break a long address across lines. Ask for the whole link again and paste it into the address bar.

Tapped the wrong one? Undo steps back to the previous match, and you can keep stepping back. Starting over reshuffles the order from scratch.

If the link you made looks very long, fewer or shorter options shorten it. The list itself travels inside the address, so a long list means a long address. It still works the same either way.