The PERCENTILE function in Excel is a statistical function used to calculate the rank of a given value in a data set.

It’s useful for **determining the percentile rank of a given value,** meaning what percentage of values in the data set **is equal to or less than the given value. **

The function takes two arguments, both of which are required.

- The first argument is the array of values or the data set;
- The second argument is the percentile value you want to calculate the rank of. This value must be between 0 and 1 and specifies the fraction of the data set that is equal to or less than the given value.

For example, if the percentile value you specify is 0.5, the function will return the 50th percentile, or the median, of the data, set.

The median is the middle value in a sorted list of values. If the percentile value you specify is 0.9, the function will return the 90th percentile or the value that is greater than or equal to 90% of the values in the data set.

The PERCENTILE formula is useful for interpreting the relative performance of a value in a data set. It can be used to determine the relative ranking of test scores, employee performance, investment returns, or any other type of data set.