statistics
Probability Calculator
Calculate event unions, conditional probability, Bayes' theorem, binomial probabilities, and normal-distribution areas.
Calculator
Formula
P(A∪B), P(A|B), Bayes, Binomial, Normal
Assumptions and limits
- Inputs are finite real numbers unless an integer or probability is explicitly required.
Example
Editable worked example
The calculator starts with an editable example.
Sources
Frequently asked questions
Are my inputs uploaded?
No. This calculator runs locally in your browser. Inputs are placed in a URL only when you explicitly copy a share link.
Why are units converted first?
Canonical units prevent scale errors when inputs use mixed units. The result is converted back to your selected output unit afterward.
Does the result replace professional judgment?
No. The result applies only to the stated model and assumptions. Qualified people should review high-risk engineering, medical, or laboratory decisions.