Probability Calculator
Calculate combinations, permutations, binomial probability, and expected values.
Calculator Mode
n (total)
r (choose)
Result
120
C(10, 3) = 10! / (3! * 7!) = 120
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About Probability Calculator
Compute probabilities for common scenarios — single and combined events, complements, and conditional probability. A handy check for stats homework and decision-making.
How to use
- Choose the type of probability you want to compute.
- Enter the event probabilities or counts.
- Read the calculated result.
Frequently asked questions
- How do I combine independent events?
- Multiply their probabilities for "and"; for "or" of mutually exclusive events, add them.
- What is a complement?
- The complement of an event is 1 minus its probability — the chance it does not happen.