Defects per Unit (DPU)

The average number of defects per unit. The ratio of defects to unit is the universal measure of quality.


D: number of Defects

U: number of Units


Defects Per Unit

DPU may be estimated if the Throughput Yield (also called First Pass Yield) is known:

Take this table shown below as an example.

Ten nails were produced at a manufacturing facility and each nail has five ways (opportunities) it can be defective. If any one of the five characteristics fails, then the entire nail is considered defective.


There is a possibility of 50 total defects if each nail had all five characteristics (opportunities) fail.

The total number of defects (D) is 2+1+3+2+3+4+2+2 = 19.

The number of defectives is 8.

8 out of 10 nails contained one or more defects qualifying them as defective.

From the table:

D = 19 total defects were found

U = 10 units (nails)

DPU = 1.9 defects per nail

If all these defects could come from a SINGLE process (not in reality for this case, these types of defects occur from different operations), rearranging the formula above the TPY is:

TPY calculation from DPU

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