How to Calculate CPK With Excel

By Jaime Avelar

Learning how to calculate CPK in Microsoft Office Excel can save you time if you’re planning on doing statistical data calculations. CPK is used to measure how centered the sample data is from a specified limit. In order for you to calculate CPK you need to calculate the average of your sample data by using the “Average” function. In addition, you need to calculate the standard deviation using the “STDEV” function. This function measures how far the values are dispersed from the average value.

Step 1

Launch Microsoft Excel and type “Data” in A1, “Upper Limit” in B1, “Average” in C1, “StDev” in D1, and “Cpk” in E1.

Step 2

Type “1” in A2, “2” in A3, “3” in A4, “4” in A5, “5” in A6, “6” in A7, “7” in A8, “8” in A9, “9” in A10, and “10” in A11. Type “15” in B2.

Step 3

Add the following formula in C2 to calculate the average for the data:=AVERAGE(A2:A11)

Step 4

Add the following formula in D2 to calculate the standard deviation for the data:=STDEV(A2:A11)

Step 5

Calculate CPK using the upper limit, average, and standard deviation values by adding the following formula in E2:=((B2-C2)/(3*D2))