NORM.INV
TheNORM.INV
function returns the inverse of the cumulative normal distribution for a specified mean and standard deviation. It is commonly used in statistical analysis to find the value at which a specified percentage of observations occur below that value.
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NORM.INV
formula?  Examples of using
NORM.INV
formula NORM.INV
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NORM.INV
Usage
Use the NORM.INV
formula with the syntax shown below, it has 3 required parameters:
 x (required):
The probability of the value occurring below the mean.  mean (required):
The arithmetic mean of the distribution.  standard_deviation (required):
The standard deviation of the distribution.
Examples
Here are a few example use cases that explain how to use theNORM.INV
formula in Google Sheets.
Finding the zscore for a given probability
Suppose we want to find the zscore for which there is a 25% chance of getting a value lower than that. We can use NORM.INV
with x = 0.25
, mean = 0
and standard_deviation = 1
to find this value.
Generating a random sample from a normal distribution
We can use the RAND
function along with NORM.INV
to generate a random sample from a normal distribution with a given mean and standard deviation. Setting x = RAND()
, mean
and standard_deviation
as desired, we can generate a random number that follows a normal distribution.
Calculating confidence intervals
Suppose we have a dataset with a normal distribution and we want to calculate a confidence interval for the mean. We can use NORM.INV
along with other functions such as AVERAGE
, STDEV.S
and COUNT
to calculate the confidence interval for a specified confidence level.
Common Mistakes
NORM.INV
not working? Here are some common mistakes people make when using the NORM.INV
Google Sheets Formula:
Incorrect arguments
One of the arguments provided is incorrect or in the wrong order. Doublecheck the syntax and ensure that the arguments are entered in the correct order.
Invalid mean or standard deviation
The mean or standard deviation provided is invalid (e.g. negative). Ensure that the mean and standard deviation are valid values.
Nonnumeric input
The input provided for x, mean, or standard_deviation is not a number. Check that the input is numeric and formatted correctly.
Related Formulas
The following functions are similar to NORM.INV
or are often used with it in a formula:

NORM.S.INV
The
NORM.S.INV
function is a statistical function in Google Sheets that returns the inverse of the standard normal cumulative distribution function for a specified value. In other words, it returns the zscore that corresponds to a given probability. This function is commonly used in hypothesis testing, confidence interval estimation, and other statistical analyses. 
NORM.DIST
The
NORM.DIST
formula is a statistical function that returns the normal distribution of a specified variable. It is used to determine the probability of a random variable falling within a specified range of values. This function is commonly used in finance and scientific research. 
NORM.S.DIST
The NORM.S.DIST function returns the standard normal cumulative distribution function. It calculates the probability that a random variable with a standard normal distribution is less than or equal to x. This function is commonly used in statistical analysis and hypothesis testing.

STDEV.P
The
STDEV.P
function is a statistical function that calculates the standard deviation of a population based on a sample of numerical data. It is commonly used to measure the amount of variation or dispersion in a dataset. The formula assumes that the input values represent the entire population, rather than a sample. If the input values represent a sample, you should use theSTDEV.S
function instead. 
AVERAGE
The AVERAGE function calculates the average (arithmetic mean) of the values passed to it. It is commonly used to find the average of a range of cells containing numerical data.
Learn More
You can learn more about the NORM.INV
Google Sheets function on Google Support.