Process Capability Calculator

To calculate a process capability analysis online, simply copy your data into the table above and then select the desired variable.

The data can be in the following formats:

The calculated process capability is then clearly displayed.

The process capability indicates how well the result of a process fits the requirements of the process. By means of the so-called process capability index, process capability becomes quantifiable and the performance of the process can be determined. Just try the online cp and cpk calculator - it's easy.

Process capability index

The process capability indices Cp and CpK are indicators for the statistical evaluation of a process in production engineering. They indicate how reliably the targets specified in the specification are achieved.

For the calculation of the process capability indices, several samples are taken from the process. The results table then displays the process capability indexes for the entire sample and those within the individual samples.

• Cp/Pp (Within/Overall): Ratio of the required tolerance window to the dispersion of the process
• Cpk/Ppk (Within/Overall): Ratio of the smallest distance to the mean value to the tolerance window and the scatter of the process

It is important to note that normally distributed data are assumed for the calculation of process capability. Otherwise it is not possible to calculate the variance of the processes in a meaningful way.

Standard deviation within samples for process capability

For the calculation of the Cpk value, the standard deviation within the samples is needed.

Cpk is calculated by using the minimum of CPL and CPU. Ppk is calculated by using the minimum of PPL and PPU.

Process capability and process performance

After the standard deviation has been calculated, the process capability Cpk and the process performance Ppk can be calculated.

Cpk Calculator

Therefore, with DATAtab it is very easy to calculate the cpk value directly online. The entered data will not be sent to any server, so you do not need to worry about data security, your data is safe when you calculate the cpk value.

Capability Calculator

The histogram shows the lower and upper specification limits as well as the target value, giving you a graphical impression what the capability of of your process is.

Within VS Overall

As explained above, samples of the process output are required for the calculation of the process capability. For example, 5 results are taken from the process at the beginning of each day, and this is repeated for 20 days. The process capability within the sample now uses the variance within each sample. The variance of all collected values is used to calculate the process capability of the entire sample or samples.