Probability

Use our free probability calculators to solve common probability problems and see how each answer is calculated. You can calculate probabilities involving two events, conditional probability, Bayes’ theorem, combinations, permutations, factorials, and other probability concepts.

Each calculator gives you an instant answer with a clear step-by-step solution, so you can follow the probability rules used instead of getting only a final number. Whether you need to find P(A ∩ B), P(A ∪ B), P(A|B), count possible outcomes, or update a probability using new evidence, choose the calculator below that matches your problem.