NORM.INV
Returns the inverse of the normal cumulative distribution for the specified mean and standard deviation. Replaces the legacy NORMINV function.
NORM.INV(probability, mean, standard_dev)Arguments
probabilityA probability corresponding to the normal distribution (between 0 and 1)meanThe arithmetic mean of the distributionstandard_devThe standard deviation of the distribution (must be > 0)
=NORM.INV(0.9088, 40, 1.5)Value of X for which P(X ≤ x) = 0.9088
=NORM.INV(0.5, 100, 10)Median equals the mean for a normal distribution
=NORM.INV(0.975, 0, 1)97.5th percentile of the standard normal distribution
- •Returns #NUM! if probability ≤ 0 or ≥ 1, or if standard_dev ≤ 0
- •Inverse of NORM.DIST with cumulative = TRUE
- •Commonly used to compute confidence interval bounds
- •Passing a probability of exactly 0 or 1 (or outside that range), which returns a #NUM! error since those extremes correspond to infinity in a true normal distribution
- •Confusing NORM.INV with NORM.DIST - NORM.INV goes from a probability to a value (the inverse direction), while NORM.DIST goes from a value to a probability
- •Passing a standard_dev of 0 or a negative number, which returns a #NUM! error since standard deviation must be strictly positive
NORM.DISTPerforms the forward operation - given a value, returns its cumulative probability, the inverse of what NORM.INV calculates.NORM.S.INVCalculates the same kind of inverse specifically for the standard normal case (mean 0, standard deviation 1), without needing to specify those parameters.CONFIDENCE.NORMUses a similar underlying calculation to construct a confidence interval margin, a common practical application of NORM.INV.Why does NORM.INV return a #NUM! error?
The probability argument is at or beyond 0 or 1, or standard_dev is zero or negative - probability must be strictly between 0 and 1, and standard deviation must be positive.
How is NORM.INV different from NORM.DIST?
They're inverse operations - NORM.DIST takes an x value and returns a probability, while NORM.INV takes a probability and returns the corresponding x value.
What's a common practical use for NORM.INV?
It's frequently used to calculate confidence interval bounds - for example, finding the x values that correspond to the 2.5th and 97.5th percentiles for a 95% confidence interval.
Need to translate a formula using NORM.INV?
Use our translator to convert your complete formula