Compare calculators

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

Chi-Square Test Calculator

Calculate the chi-square (χ²) test statistic and compare it against a critical value to test goodness of fit or independence. Used in research, biology, marketing, and quality control.

Observed Frequency 1

Expected Frequency 1

Observed Frequency 2

Expected Frequency 2

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Key differences

	Bayes' Theorem Calculator	Chi-Square Test Calculator
Category	Probability	Probability
Inputs required	3	4
Result	P(A\|B) Posterior Probability	Chi-Square Statistic
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.	Calculate the chi-square (χ²) test statistic and compare it against a critical value to test goodness of fit or independence. Used in research, biology, marketing, and quality control.