t-Test Calculator

Compare two independent samples with this two-sample (Welch’s) t-test calculator using each group’s mean, standard deviation, and size.

Sample 1 Mean

Sample 1 Standard Deviation

Sample 1 Size

Sample 2 Mean

Sample 2 Standard Deviation

Sample 2 Size

What this t-test compares

This calculator performs a two-sample (independent groups) t-test using Welch’s method, which does not assume the two groups have equal variances. It’s commonly used to test whether the means of two independent samples are significantly different.

The formula

t = (x̄₁ − x̄₂) / √(s₁²/n₁ + s₂²/n₂). Degrees of freedom are estimated using the Welch–Satterthwaite equation, which adjusts for unequal sample sizes and variances.

Compare the resulting t value against a critical value (or p-value) from a t-distribution at your chosen significance level to assess significance. This tool is for general educational and planning purposes.

Last reviewed August 2026