Process capability

The process capability is a measurable property of a process to the specification, expressed as a process capability index (e.g., Cpk or Cpm). The output of this measurement is usually illustrated by a chronological control sample, histogram and calculations that predict how many parts will be produced out of specification (OOS).

How to calculate cpk in excel

Three possibilitis:

  • add in: excel 2019, excel 2021, office 365 and microsoft account
  • template: Excel < Excel 2019 or no Microsoft Account
  • calculation online: Excel 2013 – 2021

Add in with office 365 and Microsoft Account

The base of the calculation is this spreadsheet.

You can make all adjustments like:

  • inserting your logo
  • formatting cells
  • etc., etc.

To calculate adjusted values, you need the Microsoft certified „Sixsigmablackbelt Analysis“ Excel add in.

The easiest way to get the add is to install the add in via Excel.

If you not have a template yet, push the button „Create template“. If you opened the template above, just change the values and push the button „Calculate“.


Template Excel < Excel 2019 or no Microsoft Account

Another way is to use the similar template with macros.

process capability excel template 20150102.png
process capability excel template 20150102.png

The base for the cpk formula is described here.

cpk formula excel
cpk formula excel

If you want to calculate your capabiltiy figures immediately online, check the website

cpk online calculation
cpk online calculation

If you want to to have a more scientific look on process control you can check this discussion in the minitab blog. Another way is to look on the homepage of ASQ.

Please feel free to contact me, if you have some suggestions to improve this page (


[1] (MSA) Measurement System Analysis | AIAG“. (17. April 2022).

[2] „IATF 16949-2016 | AIAG“. (17. April 2022).