Welch t-test calculator
Compare two independent means with Welch’s t-test, unequal-variance degrees of freedom, a confidence interval and a two-sided p-value. The calculation runs in your browser; your inputs stay on this device.
Welch’s t-test for two means
Compare independent groups without assuming equal variances. Enter each group’s mean, standard deviation and sample size.
Formula and assumptions
t = (mean A − mean B) ÷ √(sA²/nA + sB²/nB). Welch–Satterthwaite degrees of freedom allow unequal variances; the p-value uses Student’s t distribution.
These estimates assume independent observations and simple random samples where applicable. They do not adjust for complex designs, weighting, clustering or multiple comparisons. Read the result with the underlying study design in mind.
More statistics tools
Open the complete statistics workbench
Frequently asked questions
Are my inputs sent to PulseLake?
No. The calculation runs in your browser; the form does not submit the values, and these calculators do not use a server-side analysis service.
Do these results handle weighting or complex survey samples?
No. The methods assume independent simple random observations and do not account for weighting, clustering, repeated measures or nonresponse.
Does statistical significance establish practical importance?
No. Review the interval and whether effects of that size matter for the decision. A non-significant result does not prove groups are identical.
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