RANK function
Returns the rank of a number in a list of numbers. The rank of a number is its size relative to other values in a list. (If you were to sort the list, the rank of the number would be its position.)
Important This function has been replaced with one or more new functions that may provide improved accuracy and whose names better reflect their usage. This function is still available for compatibility with earlier versions of Excel. However, if backward compatibility is not required, you should consider using the new functions from now on, because they more accurately describe their functionality.
For more information about the new functions, see RANK.AVG function and RANK.EQ function.
Syntax
RANK(number,ref,[order])
The RANK function syntax has the following arguments:

Number Required. The number whose rank you want to find.

Ref Required. An array of, or a reference to, a list of numbers. Nonnumeric values in ref are ignored.

Order Optional. A number specifying how to rank number.
If order is 0 (zero) or omitted, Microsoft Excel ranks number as if ref were a list sorted in descending order.
If order is any nonzero value, Microsoft Excel ranks number as if ref were a list sorted in ascending order.
Remarks

RANK gives duplicate numbers the same rank. However, the presence of duplicate numbers affects the ranks of subsequent numbers. For example, in a list of integers sorted in ascending order, if the number 10 appears twice and has a rank of 5, then 11 would have a rank of 7 (no number would have a rank of 6).

For some purposes one might want to use a definition of rank that takes ties into account. In the previous example, one would want a revised rank of 5.5 for the number 10. This can be done by adding the following correction factor to the value returned by RANK. This correction factor is appropriate both for the case where rank is computed in descending order (order = 0 or omitted) or ascending order (order = nonzero value).
Correction factor for tied ranks=[COUNT(ref) + 1 – RANK(number, ref, 0) – RANK(number, ref, 1)]/2.
In the following example, RANK(A2,A1:A5,1) equals 3. The correction factor is (5 + 1 – 2 – 3)/2 = 0.5 and the revised rank that takes ties into account is 3 + 0.5 = 3.5. If number occurs only once in ref, the correction factor will be 0, since RANK would not have to be adjusted for a tie.
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.

