{"id":22549,"date":"2026-04-15T10:00:05","date_gmt":"2026-04-15T09:00:05","guid":{"rendered":"https:\/\/ezfactory.nl\/?p=22549"},"modified":"2026-04-02T14:07:16","modified_gmt":"2026-04-02T13:07:16","slug":"what-is-the-sigma-level-how-to-calculate-the-quality-of-your-process","status":"publish","type":"post","link":"https:\/\/ezfactory.nl\/en\/knowledge-base\/what-is-the-sigma-level-how-to-calculate-the-quality-of-your-process\/","title":{"rendered":"What is the Sigma level? How to calculate the quality of your process!"},"content":{"rendered":"
[vc_row][vc_column][vc_column_text css=””]In a factory, everything revolves around quality, efficiency, and predictability. The fewer errors there are in a process, the higher the product quality and the lower the costs. An important way to measure the quality of a process is by determining the Sigma level. The Sigma level shows how well a process performs and how many errors occur on average. And here is the good news: you can calculate the Sigma level of your factory yourself!<\/span><\/p>\n

What is the Sigma level and why is it so important?<\/span><\/h2>\n

The Sigma level is a statistical measure that indicates how often errors occur in a process. The higher the Sigma level, the fewer defects and errors occur. A high Sigma level therefore means that a process operates very consistently and produces hardly any errors. A low Sigma level, on the other hand, indicates high variation and a greater chance of defective products.<\/span><\/p>\n

The concept of calculating the Sigma level originates from the Six Sigma methodology, which is used worldwide to improve processes and reduce variation. For factories, this has a direct impact on product quality, production costs, customer satisfaction, and process stability. By maintaining control over the Sigma level, organisations can more effectively manage the performance of their production processes.<\/span><\/p>\n

What are the Sigma levels?<\/span><\/h2>\n

Sigma levels are often expressed in relation to the number of defects per million opportunities (DPMO \u2013 Defects Per Million Opportunities). The table below shows the different Sigma levels and the percentage of defect-free production associated with each level.<\/span><\/p>\n\n\n\n\n\n\n\n\n\n\n
Sigma level<\/th>\nDefects per million opportunities (DPMO)<\/th>\nPercentage defect-free<\/th>\n<\/tr>\n<\/thead>\n
1 Sigma<\/td>\n690.000<\/td>\n31%<\/td>\n<\/tr>\n
2 Sigma<\/td>\n308.000<\/td>\n69%<\/td>\n<\/tr>\n
3 Sigma<\/td>\n66.800<\/td>\n93,3%<\/td>\n<\/tr>\n
4 Sigma<\/td>\n6.210<\/td>\n99,38%<\/td>\n<\/tr>\n
5 Sigma<\/td>\n233<\/td>\n99,977%<\/td>\n<\/tr>\n
6 Sigma<\/td>\n3,4<\/td>\n99,99966%<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

In traditional production processes, an average Sigma level of 3 or 4 is typically achieved. In contrast, organisations that operate according to the Six Sigma principle aim to reach Sigma level 6, where virtually no errors occur.<\/span><\/p>\n

Calculate the Sigma level of your factory performance<\/span><\/h2>\n

You can only calculate the Sigma level of a process once you have gathered all the necessary data from the production process. This includes:<\/span><\/p>\n