Statistics

Upper Control Limit Calculator

Find the control chart limits from the mean and standard deviation.

Calculated Output

Upper control limit 56

Lower control limit 44

Formula: UCL = mean + kσ; LCL = mean − kσ

Step-by-Step Breakdown

1. Values used:

2. Process mean = 50

3. Standard deviation = 2

4. Sigma multiple = 3

6. Upper control limit = 56

7. Lower control limit = 44

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The math behind it

UCL = mean + kσ, LCL = mean − kσ, usually with k = 3 (the 3-sigma rule).

Mean 50, σ 2, 3σ → UCL 56, LCL 44.

What does crossing a limit mean?

A likely special cause — the process may be out of control.