The Excel PERCENTILE.INC function calculates the “kth percentile” for a set of data where k is 0 to 1, inclusive. A percentile is a value below which a given percentage of values in a data set fall. You can use PERCENTILE.INC to determine the 90th percentile, the 80th percentile, etc.
Syntax:= PERCENTILE.INC(array,k)
The PERCENTILE.INC function syntax has the following arguments:
 Array Required. The array or range of data that defines relative standing.

K Required. The percentile value in the range 0..1, inclusive.
Example: Let’s look at some Excel PERCENTILE.INC function examples and explore how to use the PERCENTILE.INC function as a worksheet function in Microsoft Excel:
Syntax: =PERCENTILE.INC(B2:B17,C2)
Result: 9.25
Based on the Excel spreadsheet above, the following PERCENTILE.INC examples would return:
Syntax: =PERCENTILE.INC(B2:B17,C2)
Result: 8.5
Syntax: =PERCENTILE.INC(B2:B17,C4)
Result: 8.5
Syntax: =PERCENTILE.INC(B2:B17,C5)
Result: 8.4
Syntax: =PERCENTILE.INC(B2:B17,C6)
Result: 8.1
Syntax: =PERCENTILE.INC(B2:B17,C7)
Result: 7.15
Syntax: =PERCENTILE.INC(B2:B17,C8)
Result: #NUM!
Note:
 If array is empty, PERCENTILE.INC returns the #NUM! error value.
 If k is nonnumeric, PERCENTILE.INC returns the #VALUE! error value.
 If k is < 0 or if k > 1, PERCENTILE.INC returns the #NUM! error value.

If k is not a multiple of 1/(n – 1), PERCENTILE.INC interpolates to determine the value at the kth percentile.