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Probability Calculator

Calculate odds and chances of success.

Single Trial
Multiple Trials

Example: Rolling a 4 on a 6-sided die (1 success, 6 total).

Calculates the chance that the event happens at least once.

Chance of Success
16.67%
Odds (1 in X)
1 in 6.00
0% 100%
Failure: 83.33%

Understanding Probability

Single Trial

For a single event, probability is the ratio of the number of favorable outcomes to the total number of possible outcomes.

P(A) = Successes / Total

The "Odds" (1 in X) represent the reciprocal of the probability, often used in gambling or risk assessment.

Multiple Trials

When calculating the probability of an event happening at least once in multiple independent trials, it is easier to calculate the chance that it never happens.

P(At least 1) = 1 - P(None)

Where P(None) = (1 - P(one trial))n.