NORM.S.INV function
Returns the inverse of the standard normal cumulative distribution. The distribution has a mean of zero and a standard deviation of one.
Syntax
NORM.S.INV(probability)
The NORM.S.INV function syntax has the following arguments:

Probability Required. A probability corresponding to the normal distribution.
Remarks

If probability is nonnumeric, NORMS.INV returns the #VALUE! error value.

If probability <= 0 or if probability >= 1, NORMS.INV returns the #NUM! error value.
Given a value for probability, NORM.S.INV seeks that value z such that NORM.S.DIST(z,TRUE) = probability. Thus, precision of NORM.S.INV depends on precision of NORM.S.DIST. NORM.S.INV uses an iterative search technique.
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. If you are copying the example in Excel Web App, copy and paste one cell at a time.
Important Do not select the row or column headers.
Selecting an example from Help

Press CTRL+C.

Create a blank workbook or worksheet.

In the worksheet, select cell A1, and press CTRL+V. If you are working in Excel Web App, repeat copying and pasting for each cell in the example.
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.


Note The value of the result depends on the number of decimal places that are used in the number format of the cell that contains the formula.