Statistical

NORM.S.INV Function in Excel

Returns the inverse of the standard normal cumulative distribution.

Syntax

  • =NORM.S.INV(probability)

Arguments

  • probability (required): Probability (0 to 1)

Examples

  • =NORM.S.INV(0.975) - Z-score for 97.5% - Result: 1.96

NORM.S.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

  • Z-scores
  • Critical values
  • Confidence intervals

Frequently asked questions

  • What is NORM.S.INV used for? NORM.S.INV returns the z-score corresponding to a given probability in the standard normal distribution. It's essential for finding critical values in hypothesis testing and constructing confidence intervals without needing to look up z-tables.
  • How do I find common critical z-values? For 95% confidence (two-tailed): =NORM.S.INV(0.975) returns 1.96. For 99%: =NORM.S.INV(0.995) returns 2.576. For one-tailed 95%: =NORM.S.INV(0.95) returns 1.645. These are the z-values that cut off the specified tail areas.
  • How do I use NORM.S.INV for confidence intervals? For a 95% CI of a mean: margin = NORM.S.INV(0.975) * (stdev/SQRT(n)). Then CI = mean ± margin. Example: mean=50, stdev=10, n=100: margin = 1.96 * (10/10) = 1.96, so CI is 48.04 to 51.96.

Editorial review

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