Best-of-N Series Win Probability Calculator
Turn one team’s chance of winning a single game into its chance of winning a best-of-3, 5, 7 or 9 playoff series. Free, private and instant.
How to use the Best-of-N Series Win Probability Calculator
- Enter the chance that team A wins any single game, as a percentage. You can base it on ratings, odds or your own judgement.
- Choose the series length: best of 3, 5, 7 or 9.
- Read each team’s chance of winning the series, the chance of each exact result and the expected number of games.
- Use the length table to see how the same single-game edge grows in a longer series.
Example
Worked example (a team with a 60% chance each game, run through this tool)
- Best of 7: Team A wins the series 71.02% of the time, team B 28.98%
- Best of 5: 68.26%
- Best of 3: 64.8%
- Best of 1: 60% (a single game)
- Expected length of a best of 7: About 5.7 games
Limitations
- The calculator assumes each game is independent and that team A has the same chance in every game. Home-court advantage, injuries and momentum are not modelled.
- The single-game chance is an input, not something the tool can predict. Garbage in, garbage out.
- Ties and draws are not handled, so it suits sports and games that always produce a winner.
- It does not use real teams or live data and it is not betting advice.
Sources
About this tool
The Series Win Probability Calculator converts a single-game win chance into the chance of winning a best-of-N series, which is how playoffs in basketball, hockey, baseball and many esports work. Enter the chance that team A wins any one game, choose the series length, and it shows each team’s series chance, the probability of each exact result such as 4–2, the expected number of games, and a comparison across series lengths. It shows how much a longer series favours the stronger team.
Also searched for as: best of 7 probability, playoff series odds calculator, series win probability, best of five odds, playoff odds calculator.
Best-of-N Series Win Probability Calculator is part of ToolStack Hub's Calculators. It runs entirely in your browser, which keeps your data private and makes results instant. There is nothing to install and no account to create. There is no usage limit.
Guides about this tool
Frequently asked questions
How do I calculate the chance of winning a best-of-7?
A team needs four wins. Add up the chance of winning in 4, 5, 6 or 7 games, where winning in g games has probability C(g−1, 3) × p^4 × (1−p)^(g−4). The calculator does it for you.
Does a longer series favour the better team?
Yes. A team with a 60% chance per game wins 60% of single games, 64.8% of best-of-3 series, 68.3% of best-of-5 and 71.0% of best-of-7 series.
Why is a best-of-7 not twice as good as a best-of-3?
The advantage grows slowly. The more games, the more the better team’s edge shows, but upsets remain possible.
Can I use bookmaker odds as the single-game chance?
You can convert odds to an implied chance and remove the bookmaker’s margin first. The calculator takes the final percentage.
Is this tool for betting?
No. It is a probability calculator, not advice, and it does not predict real results.
Is the Best-of-N Series Win Probability Calculator free?
Yes. Best-of-N Series Win Probability Calculator is completely free with no sign-up, limits or watermarks.
Is my data private when I use the Best-of-N Series Win Probability Calculator?
Yes. It runs in your browser, so your input is not uploaded to our servers.
Does it work on mobile?
Yes. ToolStack Hub tools work on phones, tablets and desktop browsers.
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