Probability
Calculator

Calculate single event probability, combined event probability, and conditional probability with instant results.

Single Event

Probability

0.1667

Percentage

16.6667%

Odds

1 to 5

Combined Events

Assumes independent events

P(A and B)

0.15

P(A or B)

0.65

P(not A)

0.5

P(not B)

0.7

Conditional Probability

P(A | B) = P(A and B) / P(B)

P(A | B)

0.5

Learn more

What does 95% confidence actually mean, and how do z-scores work?

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Frequently Asked Questions

Probability equals the number of favorable outcomes divided by the total number of possible outcomes. For example, rolling a 3 on a six-sided die has a probability of 1 divided by 6, or about 16.7%.

Independent events do not affect each other; the probability of one event does not change based on the outcome of another. Dependent events are linked, so the outcome of one changes the probability of the other.

For independent events, multiply their individual probabilities. For dependent events, multiply the probability of the first event by the conditional probability of the second given the first has occurred.

Probability Calculator - Calculate Event Probability | ToolsCanvas