Statistical

T.INV.2T Function in Excel

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

Syntax

  • =T.INV.2T(probability, deg_freedom)

Arguments

  • probability (required): Two-tailed probability
  • deg_freedom (required): Degrees of freedom

Examples

  • =T.INV.2T(0.05, 30) - Two-tailed critical value - Result: 2.042

T.INV.2T 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

  • Two-tailed critical values
  • Confidence intervals
  • Hypothesis testing

Frequently asked questions

  • What is T.INV.2T used for? T.INV.2T returns the positive critical t-value for a two-tailed test. Given a probability (like 0.05 for 95% confidence), it returns the t-value where that probability is split equally between both tails.
  • How do I use T.INV.2T for confidence intervals? For 95% CI: t_crit = T.INV.2T(0.05, n-1). Then CI = mean ± t_crit * (stdev/SQRT(n)). The 0.05 represents the total area in both tails (2.5% each). This is simpler than using T.INV(0.975, df).
  • What's the difference between T.INV and T.INV.2T? T.INV takes a cumulative probability and returns the corresponding t-value. T.INV.2T takes a two-tailed probability. For the same critical value: T.INV.2T(0.05, df) = T.INV(0.975, df). T.INV.2T is more intuitive for two-tailed tests.

Editorial review

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