Process Capability Learning Center

Practical guides for understanding Cp, Cpk, Pp, Ppk, histogram bins, sample size, and the assumptions behind capability calculations.

What Is Cpk?

Learn what Cpk means, how it is calculated, and why the lower of CPU and CPL controls capability risk.

Understand why Cp is potential capability while Cpk is actual capability after centering is considered.

Learn how Pp and Ppk compare with Cp and Cpk, and when overall process performance should be used.

Understand why sample size affects capability estimates and why small samples can be misleading.

Learn what histogram bins are and how square root, Sturges, Scott, custom width, and custom bin count settings change the chart.

Review the formulas, assumptions, and limitations used by this process capability calculator.