In a double-elimination tournament with 16 teams, what is the probability of a team reaching the final without losing a match?

Example Answer

I would interpret “the final” as the grand final between the winners-bracket champion and the surviving losers-bracket team. In a standard 16-team bracket with no byes, the undefeated route requires four wins: the field in the winners bracket goes from 16 to eight to four to two to one.

With a 50% chance of winning each match conditional on having reached it, a particular team's probability of arriving undefeated is (1/2)⁴ = 1/16, or 6.25%. The losers bracket does not create another undefeated path: entering it already requires a loss.

Why this works

The product uses the conditional win probability at each round. Equal skill is modeled as a fair match against every possible opponent; the calculation does not require every match in the entire tournament to pair teams with identical records.

Follow-up to prepare for

Reaching the winners-bracket final is a different event: it requires three wins and has probability 1/8 under the same assumptions. Winning the grand final is also a separate question, whose answer depends on the reset rules.