What is the Probability Calculator?
Probability tells you how likely something is, from 0 (impossible) to 1 (certain). Enter the probability of two independent events A and B (as a decimal or percentage) and see the chance of both happening, either happening, neither happening and exactly one happening.
You can also work out the probability from favourable and total outcomes – like drawing a card or rolling a die.
How to use the Probability Calculator
- Enter P(A) and P(B) as a percentage or decimal (e.g. 50 or 0.5).
- Or use the outcomes box: favourable ÷ total.
- Read all combined probabilities and the odds.
Formulas (independent events)
- P(A and B) = P(A) × P(B)
- P(A or B) = P(A) + P(B) − P(A)×P(B)
- P(not A) = 1 − P(A)
- Odds for = P : (1 − P)
This Probability Calculator is 100% free, needs no signup and runs privately in your browser – on phone, tablet or computer.
Last updated: · By NodifyTech