SPC chart builder

Paste your data to get an XmR chart with control limits, special cause signals and a plain-English reading of what the chart shows, following NHS England's Making Data Count approach.

Calculated in your browser. Nothing you paste is uploaded or saved.

Your data

Paste one value per line, or a label and a value (dates, weeks, anything). A header row is fine.

About the measure

Chart title Unit or measure label (optional) Improvement is when the value goes

Up Down Neither

Target (optional) Values can't go below zero

Control limits

Calculate from all points Fix after the first points Leave out unusually large moving ranges when calculating limits

To recalculate limits after a known change, click that point on the chart, or use the table of values.

Show moving range chart

Special cause rules

Points in a row above or below the mean Points in a row going up or down

Two of three points close to a limit

A single point outside the limits is always a signal. Defaults follow NHS England's Making Data Count guidance.

Your SPC chart

XmR chart (individuals and moving range)