Formulas and Tables

Default White Guide

SPC DEMO

Minimize Production Costs, Quickly Detect Issues, and Optimize Your Product Quality

Don’t miss out! Book a demo of our specialized SPC software and unlock immediate improvements in your processes.

Individuals and moving range chart formulas

The most common (and recommended) method of computing control limits for an individuals chart based on 3 standard deviations is:

Individuals (X)

Upper control limit

Lower control limit

Moving Range

Upper control limit

Lower control limit

Tabular values for X and range charts
Subgroup
Size
E2
D4
1
2.660
3.268
2
2.660
3.268
3
1.772
2.574
4
1.457
2.282
5
1.290
2.114
6
1.184
2.004
7
1.109
1.924
8
1.054
1.864
9
1.010
1.816
10
0.975
1.777