# How to Calculate Six Sigma

by Jamie Lisse; Updated September 26, 2017An important aspect of running a business is keeping track of quality control and your customers' satisfaction. The standard for measuring quality control and customer satisfaction is called “Six Sigma.” With Six Sigma, companies can minimize their mistakes and maximize their value to customers. There are Six Sigma consultants that offer to calculate your Six Sigma for you, but you can actually calculate Six Sigma yourself if you have the right data to do so.

Define your customer expectations. Before you can calculate Six Sigma, you will need to define your customer expectations, which is known as CTQs or Critical To Quality. If you have a flower shop your CTQs could be on-time delivery and correct orders.

Collect your CTQs data. You will need to look at your business data and examine all orders or sales to see if the orders met CTQs. Using the example above, if you have a total of 500 delivery orders and you find out that 41 of those were delivered late, and 17 were incorrect orders, then that is your CTQs data. Add up your total defects, which would be 58 in this example.

To start to calculate Six Sigma you need to divide total defects by total units. In the example above, that would be your total defects divided by your total deliveries, which would be 58 divided by 500, or 0.116.

Factor in the total number of defect opportunities. Take the total number of defect opportunities, which are your CTQs, and multiply that by the number you got when you divided your total defects by your total units. Using the example above, the total defect opportunities is 2 (delivery time and correct order). So, that means you would take 0.116 and multiply that by 2, which would equal 0.232.

Convert into Defect Per Opportunity (DPO). Once you have made your calculations you have to convert your number to DPO, which is expressed in a count by million opportunities. This means that you would move the decimal point six spaces to the right. Using the example above, the DPO would be 232,000 DPO's.