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NORMSINV Function
Summary
The NORMSINV function returns the inverse of the standard normal cumulative distribution, finding the z-score corresponding to a given probability. It assumes a mean of 0 and standard deviation of 1, essential for statistical analysis and quality control.
Syntax
NORMSINV(probability)Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
| probability | Number |
Yes | A probability value between 0 and 1 representing the cumulative distribution area |
Using the NORMSINV Function
NORMSINV is crucial for converting probabilities from standard normal tables back to z-scores. Use it in hypothesis testing, confidence intervals, and when working with z-tables where you need the critical value for a specific significance level.
Common NORMSINV Examples
Find z-score for 90.88% probability
=NORMSINV(0.9088)Returns approximately 1.3334, the z-score where 90.88% of the distribution lies to the left.
Critical value for one-tailed test (5%)
=NORMSINV(0.95)Returns 1.64485, used for α=0.05 right-tailed tests.
Two-tailed test critical value
=NORMSINV(0.975)Returns 1.95996 for α=0.05 two-tailed test (covers 97.5% area).
Frequently Asked Questions
Common Errors and Solutions
#VALUE!
Cause: Probability argument is non-numeric
Solution: Ensure probability is a valid number between 0 and 1
#NUM!
Cause: Probability ≤ 0 or ≥ 1
Solution: Use probability strictly between 0 and 1
#N/A
Cause: Iterative search failed to converge
Solution: Check probability value and consider using NORM.S.INV
Notes
- NORMSINV uses iterative technique dependent on NORMSDIST precision
- Deprecated but available for backward compatibility
- Microsoft recommends NORM.S.INV for new work
- Common in z-table reverse lookups
Compatibility
Available in: Excel 2007, Excel 2010, Excel 2013, Excel 2016, Excel 2019, Excel 2021, Microsoft 365
Not available in: Future Excel versions (recommended to migrate to NORM.S.INV)
Content last reviewed: December 9, 2025
Update frequency: As needed
Excel versions tested: Excel 2007+