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Probability Calculator

Probability of an event from favorable and total outcomes.

Worth Knowing

This computes classical probability as favorable outcomes divided by total equally-likely outcomes, giving a value between 0 (impossible) and 1 (certain). The 'equally likely' assumption is crucial and often violated in the real world — a loaded die or a biased coin breaks it. Also remember that probability describes long-run frequency, not short-term guarantees: a fair coin landing heads five times running has no memory, and the sixth flip is still an even bet.

How to Use

  1. Enter Favorable outcomes into the first field of the Probability Calculator.
  2. Fill in the rest: Total outcomes.
  3. Your result appears instantly as you type — there's no submit button or page reload.

Frequently Asked Questions