Probability Calculator

Enter favorable and total outcomes or combine two independent event probabilities to get common probability results.

Mode

Favorable outcomes

Total outcomes

—Primary result

—Complement

—P(A ∪ B)

—P(A ∩ B)

—Enter probabilities as decimals from 0 to 1 in two-event modes.

How to use this Probability Calculator

Calculate simple event probability, odds, and complements. Enter your values above and the result is calculated directly in your browser. No account is required.

Fast answer, clear inputs

This tool is built around one job: give the answer quickly without forcing a signup or hiding the result. Related tools are linked nearby when the next calculation or conversion is useful.