SPC Control Chart Generator

Generate X̄-R and I-MR control charts with capability analysis

Select Chart Type

X̄-R Chart

For subgroups of 2-10 measurements. Monitors process mean and range. Each line = one subgroup.

I-MR Chart

For individual measurements (subgroup size = 1). Uses moving range. One value per line.

Enter Measurement Data

Enter one subgroup per line. Separate values with spaces, commas, or tabs.

Process Capability

Chart 1

Chart 2

Out-of-Control Signals (Nelson Rules)

About SPC Control Charts

Statistical Process Control (SPC) charts monitor process stability over time. Control limits are calculated from the data itself (±3 sigma), distinct from specification limits.

A process is "in control" when all points fall within control limits and show no non-random patterns. Capability indices (Cp, Cpk) compare process spread to specification tolerance.