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Attribute Cp Cpk Calculator in Excel

Calculating Cp Cpk for Go/No-Go and Pass/Fail Gages

Calculating Process Capability for attribute data can seem tricky. That is why we created the Cp Cpk Calculator and Cp Cpk Template in Excel. These templates are part of the proven and affordable QI Macros SPC Software for Excel.

Instructions for Using the Cp Cpk Calculator with Attribute Data

1. Click on the QI Macros menu on Excel's toolbar and select Calculators. Then click on the DPMO | Yield | Cp/PPM | OEE:




2. In the template, click on the tab labeled Cp-Cpk-PPM calculator. Input areas are shaded yellow:



3. Enter PPM above/below the Go/NoGo in cells B2 and B3 to calculate Cp Cpk
   • if you are using a pass/fail or go/nogo gage, some parts are too large, some are too small. This is like a specification limit. Calculate Parts Per Million (PPM) using:
     - PPM Above = (Parts too large*1000000)/Total Parts
     - PPM Below = (Parts too small*1000000)/Total Parts
   • Put these values in the Cp/Cpk calculator to determine Cp and Cpk.

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Instructions for Using the Cp Cpk Template with Attribute Data

In September, 2016, we added this calculation to the Cp Cpk Template:

1. Click on Capability Templates > Cp Cpk Templates:
   



2. Next click on the worksheet tab labeled: Pass-Fail Cp Cpk Calculator.
3. Enter the parts that failed the go/nogo test in Cells B2:B3 and Total Parts in cell B4.
   These will be converted to Z scores which are then converted to Cp and Cpk:
   

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