T-Test Calculator
Enter your data to compute a t-test — one-sample, independent two-sample (Welch) or paired — with the t value, df and p-value.
How to use it
- Choose the test type One-sample, two-sample or paired.
- Enter your data Separate numbers with commas, spaces or new lines.
- Read the result See the t statistic, degrees of freedom and the two-tailed p-value.
Examples
| One-sample | mean vs μ₀ |
|---|---|
| Two-sample | group A vs B |
About this tool
A t-test checks whether the difference between averages is likely to be real or just down to chance. This calculator runs the three common versions: one-sample (compare a mean to a target), independent two-sample (compare two groups, using Welch’s method), and paired (before-and-after measurements).
For each test you get the t statistic, the degrees of freedom and a two-tailed p-value, computed with the Student’s t distribution. Results are for general analysis and education; choosing the right test and interpreting it depends on your study design. Everything runs in your browser.
Frequently asked questions
What does the p-value mean?
It is the probability of seeing a difference at least this large if there were really no difference. By convention, p < 0.05 is treated as statistically significant.
Which two-sample test is used?
Welch's t-test, which does not assume the two groups have equal variances and is the safer default.
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Updated June 12, 2026