Statistical

T.INV Function in Excel

Returns the left-tailed inverse of the Student's t-distribution.

Syntax

  • =T.INV(probability, deg_freedom)

Arguments

  • probability (required): Probability (0 to 1)
  • deg_freedom (required): Degrees of freedom

Examples

  • =T.INV(0.95, 30) - t critical value - Result: 1.697

T.INV 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

  • #NUM! if probability not between 0 and 1

Use cases

  • Critical values
  • Confidence intervals
  • Hypothesis testing

Frequently asked questions

  • What is T.INV used for? T.INV returns the t-value (critical value) for a given left-tail probability. It's the inverse of T.DIST. Use it to find critical values for one-tailed t-tests or to construct one-sided confidence intervals.
  • How do I find critical t-values for hypothesis testing? For one-tailed test at α=0.05 with df=25: =T.INV(0.95, 25) for upper tail, =T.INV(0.05, 25) for lower tail. For two-tailed tests, use T.INV.2T instead, or =T.INV(1-α/2, df) for the positive critical value.
  • How do I use T.INV for confidence intervals? For a 95% CI with sample size n: t_crit = T.INV(0.975, n-1). Then CI = mean ± t_crit * (stdev/SQRT(n)). Use 0.975 because you want 2.5% in each tail for a two-sided 95% interval.

Editorial review

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