Win Probability Added (WPA) tells you how much a player’s action changed his team’s chance of winning.
Use our calculator to get an instant number from any play.
Enter the team’s win probability before the play and after it, and the tool will return the exact WPA in percentage points.
It is a quick way to turn game context into a single, intuitive metric you can discuss and compare.
Win Probability Added (WPA) Calculator
Frequently Asked Questions
What is Win Probability Added?
Win Probability Added, or WPA, measures how much a single event changed a team’s chance of winning.
A positive number means the play increased the chance; a negative number means it hurt the chance.
How is WPA different from win probability?
Win probability is a snapshot at a given moment, while WPA is the difference between two snapshots, isolating the impact of a play.
Why use percentage points instead of decimals?
Expressing WPA in percentage points is easier to read and discuss.
Saying a player added 3.4 percentage points is clearer than saying 0.034.
Can WPA be negative?
Yes.
If a play decreases the team’s win probability, the calculator will output a negative WPA value.
Where do I find win probability numbers to use?
Many sports sites publish live win probability charts.
You can also generate them with public play-by-play data and models, then plug two points into this calculator.