t-test calculator
Compare two groups and get the effect size and interval, not just a p-value.
Runs in your browser
Read in your browser. The file is not uploaded.
Welch's t-test — does not assume equal variances. The sensible default.
Paste at least two values into each group.
Formula
difference ± t(1−α/2, df) × SEModelWelch's t-test
- Welch’s correction for unequal variances — Biometrika, 1947
- Hedges’ small-sample correction to Cohen’s d — Journal of Educational Statistics, 1981
Calculated in your browser. Nothing you entered was sent anywhere.
If your values are technical replicates from a smaller number of independent experiments, your n is the number of experiments. Pooling them here will overstate significance.
About this tool
Runs Welch’s, Student’s, paired t-tests and Mann-Whitney U on pasted data. Leads with the difference between groups and its confidence interval, then the effect size, then the p-value — because that is the order in which those numbers matter.
Related tools
- Multiple testing correction — Adjust a list of p-values by Benjamini–Hochberg or Bonferroni.
Science last reviewed .