Math & Science
Probability Calculator
Calculate probability of events
Created and maintained by: CalcTago Editorial TeamLast updated: 2026-02-08
Formulas and edge cases are reviewed against authoritative references before publication. For methodology, editorial standards, or corrections, use the links below.
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Frequently asked questions
What does the Probability Calculator do?
It helps you calculate probability of events.
What inputs do I need?
Enter Favorable outcomes and Total outcomes.
Are decimals supported?
Yes, you can use decimal values where appropriate.
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About this tool
This Probability Calculator turns your inputs into practical results. Provide Favorable outcomes and Total outcomes to calculate Percentage and Probability.
Adjust values to compare scenarios and see how sensitive the result is. The calculation uses the numbers as entered, so double-check units and expect small differences from rounding in the displayed totals.