# How to Make Six Sigma Calculations in Excel

by James HighlandThe school of productivity measurement and planning known as Six Sigma aims to process project data into a quantifiable level of quality based on certain factors. The calculations used in Six Sigma analysis are strongly weighted toward a study of defect frequency in a given product or service. Microsoft Excel is a versatile tool for handling a variety of calculations, including Six Sigma. The program can easily manipulate the variables in Six Sigma analysis to provide an exact measurement of a project's likely success. It is a straightforward task in Excel that anyone trained in Six Sigma can implement immediately.

#### Step 1

Download the Six Sigma calculator spreadsheet for Excel (See References). This free worksheet is pre-formatted to utilize Excel statistical functions for Six Sigma analysis.

#### Step 2

Double-click the downloaded spreadsheet. The program will open in Microsoft Excel. A simple worksheet containing the key Six Sigma calculation variables will appear.

#### Step 3

Enter the total opportunities for defects in cell C6 of the Six Sigma calculator. This refers to the total number of occasions where a product or service could experience an overall substandard quality. For example, a manufacturing run of 1,000 identical products would offer 1,000 opportunities for defects to arise.

#### Step 4

Enter the actual number of observed defects in the data sample in cell C7. For example, a test run of 1,000 products may have resulted in 12 defects.

Study the Six Sigma analysis based on the two input variables. Only cells C6 and C7 require user input. The remaining information on the spreadsheet is automatically calculated using statistical formulas based on the number of defect opportunities and the actual number of defects. These results include the failure rate, the accuracy rate, the Sigma level and the long-term Sigma level.

#### Tips

- As noted in the Excel spreadsheet, the Six Sigma calculator takes into account a long-term improvement of 1.5 in the Sigma level. This is a standard industry practice. The formula itself is revised to add 1.5 to the statistical calculation to arrive at this number.

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