Probability Calculator — Free Online
Calculate probability for single and multiple events, combinations, and permutations online for free. Express results as fractions, decimals, and percentages.
Basic Probability
Coin Flip Simulator
About Probability Calculator
Probability measures the likelihood of an event occurring, expressed as a value between 0 (impossible) and 1 (certain). Our calculator handles basic probability, complement probability, joint probability for independent events, conditional probability, combinations (nCr), and permutations (nPr). Results are shown as fractions, decimals, and percentages. Useful for statistics students, gamblers understanding odds, data scientists, quality control professionals, and anyone studying probability theory.
Frequently Asked Questions
What is probability?
Probability is a number between 0 and 1 expressing how likely an event is. 0 means impossible, 1 means certain.
How do I calculate probability of multiple events?
For independent events, multiply their individual probabilities. For mutually exclusive events, add their probabilities.
What is the difference between combination and permutation?
Combinations count selections where order does not matter. Permutations count arrangements where order matters.
What is complement probability?
The probability that an event does NOT occur = 1 minus P(event).
Can I calculate dice and coin probability?
Yes — enter the number of outcomes and favourable outcomes for any scenario.