Bayes' Theorem Calculator

Calculate conditional probability P(A|B) using priors and likelihoods.

Unconditional Probabilities (Priors)

Probability that the hypothesis A is true before evidence
P(not A) = 0%

Conditional Probabilities (Likelihoods)

Probability of evidence B, GIVEN A is true (Sensitivity)
Probability of evidence B, GIVEN A is false
Coursera Holi Offer
Ad

Coursera Holi Offer

Build your AI fluency and get more done, faster. Get the AI skills employers are looking for and create 20+ solutions you can use at work, right away.

Start Learning
Posterior Probability P(A|B)

0%

Chance that A is true given B occurred

Probability Tree

A (0%)
B: 0%
P(A∩B)=0.00%
~A (0%)
B: 0%
P(~A∩B)=0.00%
P(A|B) = P(A∩B) / [P(A∩B) + P(~A∩B)]

Contextual Interpretation

If 0% of the population has a condition, and a test is 0% accurate (sensitivity), with a 0% false positive rate...

A person testing positive only has a 0% chance of actually having the condition.

Documentation

Bayes' Theorem

Bayes' theorem describes probability of an event, based on prior knowledge of conditions that might be related to the event.

Bayes' Theorem

Total Probability

Posterior

Frequently Asked Questions
Coursera AI Professional CertificateSponsored