NORM.INV function
Returns the inverse of the normal cumulative distribution for the specified mean and standard deviation.
Syntax
NORM.INV(probability,mean,standard_dev)
The NORM.INV function syntax has the following arguments:

Probability Required. A probability corresponding to the normal distribution.

Mean Required. The arithmetic mean of the distribution.

Standard_dev Required. The standard deviation of the distribution.
Remarks

If any argument is nonnumeric, NORM.INV returns the #VALUE! error value.

If probability <= 0 or if probability >= 1, NORM.INV returns the #NUM! error value.

If standard_dev ≤ 0, NORM.INV returns the #NUM! error value.

If mean = 0 and standard_dev = 1, NORM.INV uses the standard normal distribution (see NORMS.INV).
Given a value for probability, NORM.INV seeks that value x such that NORM.DIST(x, mean, standard_dev, TRUE) = probability. Thus, precision of NORM.INV depends on precision of NORM.DIST.
Example
The example may be easier to understand if you copy it to a blank worksheet.
How do I copy an example?

Select the example in this article.
Important Do not select the row or column headers.
Selecting an example from Help

Press CTRL+C.

In Excel, create a blank workbook or worksheet.

In the worksheet, select cell A1, and press CTRL+V.
Important For the example to work properly, you must paste it into cell A1 of the worksheet.

To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.
After you copy the example to a blank worksheet, you can adapt it to suit your needs.

