Examples
Examples
Try the starting example
- Lower specification limit (measurement units)
- 0
- Upper specification limit (measurement units)
- 12
- Process mean (measurement units)
- 7
- Within-process standard deviation (measurement units)
- 2
- Cp
- 1
- Cpk
- 0.833333
- Limiting specification side
- Upper
Try another scenario
- Lower specification limit (measurement units)
- 0
- Upper specification limit (measurement units)
- 12
- Process mean (measurement units)
- 9
- Within-process standard deviation (measurement units)
- 2
- Cp
- 1
- Cpk
- 0.5
- Limiting specification side
- Upper
Calculation method
Calculation method
Cp
(USL-LSL)/(6*sigma).
Cpk
min(USL-mean,mean-LSL)/(3*sigma).
Limiting specification side
Upper if USL-mean < mean-LSL, lower if reverse, both if equal.
Symbols and units
- a
- Lower specification limit (measurement units)
- b
- Upper specification limit (measurement units)
- c
- Process mean (measurement units)
- d
- Within-process standard deviation (measurement units)
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions & limits
Assumptions & limits
- Descriptive supplied-sigma index only. Distinguish within-process versus overall deviation. No stability, normality, pass-rate, certification or acceptance threshold is inferred. Supported limits: USL>LSL; sigma>0; finite mean; a mean outside limits can produce negative index.
Are these inputs private?
These calculations run in your browser. A shared link contains the values you choose to share. Only questions submitted to the separate AI finder are sent to OpenAI.
Further reading
Background reading; this does not imply endorsement or independent review of SumFizz.