# Converting DPMO & Sigma Level

Tools

Concepts

What does the term "Six Sigma" stand for

Black Belt Selection & Training

Applications

Does Six Sigma Work in Smaller Companies?

Six Sigma in Information Systems

Six Sigma in Staffing and Employee Relation

Six Sigma application to software projects

Importance of SPC to Six Sigma Projects

Integrating Six Sigma and Related Initiatives

Six Sigma vs. ISO 9001 and Baldrige

Difference between TQM & Six Sigma

07/27/2007

How do you covert DPMO to sigma level and sigma level to DPMO?

Al F.

Generally, you would use a table, such as provided in my Six Sigma Demystified book, or you can calculate sigma level directly in Excel using the formula =(NORMSINV(1-$D2))+1.5, where the data in cell D2 is entered as a decimal (for example, 30% error rate = 300,000 DPMO = 0.3 which would calculate Sigma Level as 2.02).

For a given sigma level, the defects per million opportunities (DPMO) is provided, assuming normality and a 1.5 sigma shift. Note that below approximately 3 sigma defects are included from both tails of the normal distribution.

Sigma |
DPMO |

1 |
697672 |

1.1 |
660083 |

1.2 |
621378 |

1.3 |
581815 |

1.4 |
541694 |

1.5 |
501350 |

1.6 |
461140 |

1.7 |
421428 |

1.8 |
382572 |

1.9 |
344915 |

2 |
308770 |

2.1 |
274412 |

2.2 |
242071 |

2.3 |
211928 |

2.4 |
184108 |

2.5 |
158687 |

2.6 |
135687 |

2.7 |
115083 |

2.8 |
96809 |

2.9 |
80762 |

3 |
66811 |

3.1 |
54801 |

3.2 |
44567 |

3.3 |
35931 |

3.4 |
28717 |

3.5 |
22750 |

3.6 |
17865 |

3.7 |
13903 |

3.8 |
10724 |

3.9 |
8198 |

4 |
6210 |

4.1 |
4661 |

4.2 |
3467 |

4.3 |
2555 |

4.4 |
1866 |

4.5 |
1350 |

4.6 |
968 |

4.7 |
687 |

4.8 |
483 |

4.9 |
337 |

5 |
233 |

5.1 |
159 |

5.2 |
108 |

5.3 |
72 |

5.4 |
48 |

5.5 |
32 |

5.6 |
21 |

5.7 |
13 |

5.8 |
9 |

5.9 |
5 |

6 |
3.4 |

Learn more about the Lean Six Sigma principles and tools
for process excellence in Six Sigma
Demystified (2011, McGraw-Hill) by Paul Keller,
in his online Lean Six Sigma DMAIC short course (**$249**), or his
online Green Belt certification course (**$499**).