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Both calculators run independently — change the inputs on either side to compare results.

Bayes' Theorem Calculator

Compute the posterior probability P(A|B) using Bayes' theorem. Use it when you want to update a prior belief about event A after observing new evidence B — common in medical testing, spam filtering, and risk analysis.

Prior Probability P(A)

P(B|A) - Likelihood

P(B) - Evidence

Fill in the required fields to see your result.

Probability

Expected Value Calculator

Compute the expected value (mean) of a discrete probability distribution by entering up to three outcomes and their probabilities. Ideal for decision analysis, gambling odds, and statistics coursework.

Outcome 1 Value

Outcome 1 Probability

Outcome 2 Value

Outcome 2 Probability

Outcome 3 Value

Outcome 3 Probability

Fill in the required fields to see your result.

Key differences

	Bayes' Theorem Calculator	Expected Value Calculator
Category	Probability	Probability
Inputs required	3	6
Result	P(A\|B) Posterior Probability	Expected Value
What it does	Compute the posterior probability P(A\|B) using Bayes' theorem. Use it when you want to update a prior belief about event A after observing new evidence B — common in medical testing, spam filtering, and risk analysis.	Compute the expected value (mean) of a discrete probability distribution by entering up to three outcomes and their probabilities. Ideal for decision analysis, gambling odds, and statistics coursework.