โ Math
Probability Calculator
For independent events, the probability of both happening is the product of the individual probabilities, and the probability of either is the sum minus the overlap. Complement gives the chance of neither.
How it works
Probability of A
Probability of B
Both A and B
Either A or B
Neither
Only A
Odds of both
Frequently asked questions
How do I use the Probability Calculator?
Fill in the fields above โ the result recalculates instantly as you type. Everything runs in your browser, so the values you enter are never collected or stored.
Is this calculator free?
Yes. It is completely free, requires no account, and works on phones, tablets and desktops.