Assumptions:
The Sigma calculator illustrated here assumes a 1.5 sigma shift. You may modify this by using the Extended mode.
Additional Information:
How to calculate Six Sigma?
Step 1: Select the process, unit & requirements
- Identify the process you want to evaluate
- What is the primary ?product? made by this process?
We refer to this "product" as UNIT
- Identify the key customer requirements for the unit
Step 2: Define the Defect opportunities
- Any failure to meet a customer requirement or performance standard is called a defect. eg. Poor paint job, wrong data etc
- Identify the number of defects that could be found on a single unit. These are Defect Opportunities
Step 3: Gather Data and calculate DPMO
- Count units produced and total defects
- Calculate defects per million opportunities (DPMO)
Step 4: Convert DPMO to Sigma
- Use the DPMO calculated in Step 3
- In the conversion table below, scroll to the row that has a value closest to the DPMO calculated above
- Find the corresponding Sigma value
See conversion table below
Alternate method
This method uses % rejection and % yield.
1. Calculate the % rejection of the process.
2. Calculate final % yield
Final % yield = 100 - (% rejection)
3. Use the %yield calculated in step 2
In the conversion table, scroll to the row which has % yield closest to the above value . Find the corresponding sigma value
Other References:
Algorithm for inverse normal cumulative distribution function