Statistics Calculators

Probability Calculator

Calculate the probability of an event based on favorable outcomes out of total possible outcomes.

Probability —

Percentage —

About the Probability Calculator

Probability measures how likely an event is to happen, expressed as a number between 0 (impossible) and 1 (certain). It's calculated by comparing the number of favorable outcomes to the total number of possible outcomes, assuming each outcome is equally likely.

Formula: P(Event) = Favorable Outcomes ÷ Total Outcomes

For example, the probability of rolling a 4 on a fair six-sided die is 1 ÷ 6 ≈ 0.1667, or about 16.67%. This basic formula underlies everything from games of chance to risk assessment.