How is probability calculated?

Probability is the number of favorable outcomes divided by the total number of possible outcomes, expressed as a fraction, decimal, or percentage between 0 and 1.

How do I find the probability of two events?

For independent events, multiply their individual probabilities. For example, the chance of flipping heads twice in a row is 0.5 × 0.5 = 0.25, or 25%.

What is the difference between independent and dependent events?

Independent events do not affect each other, like separate coin flips. Dependent events change the probability of the second given the first, like drawing cards without replacement.

What is conditional probability?

Conditional probability is the chance of an event given that another has occurred, written P(A|B). It is central to Bayes theorem and real-world reasoning under uncertainty.

What does a probability of 0 or 1 mean?

A probability of 0 means an event cannot happen; 1 means it is certain. All real probabilities fall between these bounds, and the sum of all possible outcomes equals 1.

Probability Calculator

Compute the probability of an event in seconds. The probability calculator supports single events and the combined chance of two independent events, reporting results as a fraction, decimal, and percentage.

Favorable Outcomes

Total Outcomes

Example: rolling a 6 on a die → 1 favorable out of 6 total.