Calculate the probability of winning the next N games in a row, or of a winning streak of N games anywhere in a season, from your per-game win chance.
Winning Streak Probability Formula and Method
Probability = p^n
Choose between two distinct questions. Winning the next N games uses a direct product of the same per-game probability. Finding an N-win streak anywhere in a longer window requires keeping track of consecutive trailing wins while excluding paths that have already completed a qualifying streak.
How to Use This Calculator
Select either the next N wins or a qualifying streak anywhere in a G-game window. Enter an assumed per-game win percentage and whole-number counts. The window method handles overlapping runs; G below N gives zero. Counts are bounded to N at most 1,000, G at most 10,000 and G times N at most 2,000,000 for window calculations.
Worked Example
The table’s 50% per-game chance and three specified next games give 12.5%. With the same chance and a three-win run anywhere in a ten-game window, the probability is 65/128 = 50.78125%. These are different events. Both assume independent games with a constant win probability.
0.5^3 = 0.125
Input and Example Guide
| Input or category | Example or weight | Entry guidance |
|---|---|---|
| Method | Win the next N games | Choose the convention that applies to your record. |
| Assumed win chance per game (%) | 50 | Use the stated unit; retain available precision. |
| Consecutive wins required (games) | 3 | Use a whole count in the stated unit. |
Interpreting the Result
Overlapping windows share games, so multiplying the number of possible windows by the probability of one streak generally overstates the answer. The recurrence handles overlap. This implementation tracks hit and no-hit paths separately in log space, retaining tiny positive probabilities and complements rather than subtracting nearly equal numbers. A near-certain interior result rounded to 100% is marked approximately 100%; it is not a guarantee. Both methods assume independent games and constant probability: a changing schedule, player availability, or dependence between outcomes needs a different model.
The probability of the next N wins differs from a streak somewhere in a longer window. Overlapping streaks are not independent.
Assumptions and Common Input Errors
The model treats outcomes as independent with the same win probability. The win chance is a supplied assumption, not inferred from a record. A draw is a non-win in this binary model. A blank field is not treated as zero; enter 0% explicitly for an assumed impossible win. Up to twelve decimal places are accepted for the percentage.
Saving and Revising a Scenario
A successful calculation is saved in this browser and can be restored on the next visit. Editing an input marks the displayed saved result as stale until Calculate is selected again. Reset clears this calculator’s saved data and returns the required inputs to blank. Only validated saved inputs are recomputed; saved HTML is ignored.
