Bayes' Theorem
Calculate Bayes' Theorem instantly with the exact formula and a worked example. Free online calculator — no signup, works on mobile.
Bayes' Theorem
P(A)
P(B|A)
P(B|¬A)
P(A|B)
0.161017
More about: Bayes' Theorem
What it calculates
The “Bayes' Theorem” calculator computes P(A|B) from 3 parameters: p(a), p(b|a), p(b|¬a).
A core calculation for studying, engineering tasks, and checking solutions.
Example calculation
With parameters P(A) = 0.01, P(B|A) = 0.95, P(B|¬A) = 0.05 the result is 0.161.
How to use
- Enter the parameter values — every field above is adjustable with a slider.
- The result and related metrics are calculated automatically as you type.
- Use the additional metrics shown (if any) where needed.
- Copy the result or bookmark the page.