Statistical

T.TEST Function in Excel

Returns the probability associated with a Student's t-test.

Syntax

  • =T.TEST(array1, array2, tails, type)

Arguments

  • array1 (required): First data set
  • array2 (required): Second data set
  • tails (required): 1 for one-tailed, 2 for two-tailed
  • type (required): 1=paired, 2=equal var, 3=unequal var

Examples

  • =T.TEST(A1:A10, B1:B10, 2, 2) - Two-sample t-test - Result: p-value

T.TEST for data analysis

  • Confirm whether you need entire columns, filtered subsets, or distinct values.
  • Use [COUNTIFS](/functions/countifs/) and [SUMIFS](/functions/sumifs/) for multi-criteria metrics.
  • Pivot tables complement single-cell statistical formulas for exploration.

Common errors

  • Arrays must have at least 2 values

Use cases

  • Mean comparison
  • Hypothesis testing
  • A/B testing

Frequently asked questions

  • What is T.TEST used for? T.TEST performs a t-test and returns the p-value, testing whether two samples have significantly different means. It's essential for A/B testing, comparing treatment vs control groups, and determining if observed differences are statistically significant.
  • What do the type parameter options mean? Type 1: Paired t-test (same subjects measured twice, like before/after). Type 2: Two-sample assuming equal variances. Type 3: Two-sample assuming unequal variances (Welch's t-test, most commonly used). When unsure, use type 3.
  • How do I interpret T.TEST results? T.TEST returns a p-value. If p < 0.05, the difference is statistically significant at 95% confidence. Example: =T.TEST(A1:A20, B1:B20, 2, 3) returns 0.03, meaning there's only 3% chance the difference is due to random variation - likely a real difference.

Editorial review

  • Reviewed by Excel.Directory Editorial Team. Updated May 2026.