Brier Score Calculator
Grade how sharp a probability forecast was.
Enter your forecast probability and what actually happened (1 = it happened, 0 = it didn’t). See the Brier score — lower is sharper.
What is a Brier score?
The Brier score measures how accurate a probability forecast was — the squared difference between what you predicted and what happened. 0 is a perfect call, 1 is as wrong as possible, and 0.25 is what you’d get guessing 50/50. Track it over many predictions to see if your probabilities are actually calibrated.
Sharp App does this automatically across 100+ sportsbooks and apps — see the Prediction Markets.
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