How to create formula to find relative percent difference in Excel

[Aarti C]

I'm trying to develop a data control chart and I can't find the function for relative percent difference...I think it might be a nested function that I need to use? I'm new to this aspect of excel so, please be kind. I have found the formula ABS (A-B)/A but I need a function for relative percent difference. So how can I change the following formula into something that works in excel? (a-b)/((a+b)/2)*100 = relative percent difference, where a is a data point in column A and b is a data point in column B?

[Shurod]

In an empty cell, just replace the a and b with the actual cell references and then place an = sign in front.

=(A2-B2)/((A2+B2)/2)*100

where cell A2 contains your a data point and cell B2 contains your b data point.