NORM.S.INV Function in Excel: Z-Score for a Probability

⏱ 1 min readUpdated 28 September 2026

StatisticsLevel: ExpertAvailable in: Excel 2010+

In this article
  1. Syntax
  2. Examples
  3. Example 1
  4. Example 2
  5. Related functions

NORM.S.INV returns the z-score for a cumulative probability — where the famous 1.96 comes from.

Syntax

=NORM.S.INV(probability)
Argument What it means
probability Between 0 and 1.

Examples

Example 1

=NORM.S.INV(0.975)

About 1.96.

Example 2

=NORM.S.INV(0.95)

About 1.645, the z for 95% service level in safety-stock formulas.

NORM.S.DIST · NORM.INV

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