Probability Calculator
What are the odds? Enter the number of favorable outcomes and the total possible outcomes to get the probability as a fraction, a decimal and a percent — plus the chance of the opposite event happening.
Enter values — the result will show here live.
How to use
- Enter the total possible outcomes, like 6 on a dice.
- From these, enter the favorable outcomes, like one specific number = 1.
- You will get the probability, its percent, and the probability of the opposite event (complement).
Tips
- Favorable outcomes can never exceed total outcomes — fix your counts if the tool warns you.
- For "at least one" problems, compute 1 minus the probability of none — it is much simpler.
- Percent, fraction and decimal are the same answer — use whichever your class or report needs.
Note: Formula: P(event) = favorable / total. Favorable cannot be more than total. This is simple (theoretical) probability.