Math calculators

Probability Calculator

Enter probabilities between 0 and 1 for two independent events to get AND and OR results.

P(A and B)

0.15

P(A or B)

0.65

How to use

  1. Enter P(A) and P(B) as decimals from 0 to 1.
  2. Read P(A and B) and P(A or B).
  3. Keep events independent for these formulas.

Features

  • Independent AND / OR
  • Decimal probability inputs
  • Clear results

Privacy & how it works

This calculator runs entirely in your browser with JavaScript. Your inputs are not uploaded to ToolsWeb servers for this tool. Privacy Policy · Disclaimer.

FAQ

What about dependent events?expand_more

These formulas assume independence. Dependent events need conditional probability.

Is this calculator free?expand_more

Yes. No signup required.

Are my numbers uploaded?expand_more

No. Calculations run in your browser. Inputs are not sent to ToolsWeb servers for this tool.

Is this professional advice?expand_more

No. Results are estimates for general information. See our Disclaimer for health, finance, and related tools.