Free, no-sign-up statistics calculators built by qualified statisticians. Each one explains what your result means in plain English — and if you would rather hand the analysis to an expert, every tool links to a fixed-price service.
Sample Size Calculator
How many participants your study needs.
T-Test Calculator
Compare two group means, with a full write-up.
Chi-Square Calculator
Test associations between categories.
Confidence Interval Calculator
Put a margin of error around a mean.
Statistical Power Calculator
Check your study can detect a real effect.
Z-Score Calculator
Convert a value to a z-score and percentile.
P-Value Calculator
Turn a test statistic into a p-value.
Mann-Whitney U Calculator
Compare two groups without assuming normality.
Which Statistical Test?
Answer three questions, get the right test.
Need the analysis done for you?
Upload your data and a qualified statistician will run the tests and write up the results. Fixed price, delivered by email — no calls.