Probability Calculator

Three modes for common probability problems: basic probability from outcomes, combined probability for two events (with AND/OR options), and complement probability. Useful for stats homework or just satisfying curiosity.

How to use

  1. For basic probability, enter how many favourable outcomes and how many total outcomes there are.
  2. For two events, switch to that tab and enter the probability of each event as a percentage.
  3. The complement tab finds P(A') - the probability that A does NOT happen.