# Calculating Defect Rate or Percent of Rejection

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#### jm1231

How do i get % of reject? Is it total reject/total produced(reject+good)X100, or total reject/total good X100?

#### harry

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How do i get % of reject? Is it total reject/total produced(reject+good)X100, or total reject/total good X100?
Welcome to the forum.

If you are talking about a single part (not an assembly of various parts), the the first formula is correct. In terms of presentation: [total reject/total produced(reject+good)]X100

J

#### jm1231

Welcome to the forum.

If you are talking about a single part (not an assembly of various parts), the the first formula is correct. In terms of presentation: [total reject/total produced(reject+good)]X100

If i will use the first formula, if i had a good products of 5 pieces but i had produced a 10 defectives (meaning 15 pieces were produced) the rejection rate is 66.67%. Well in fact the rejects are greater than good, then if i will use the second one, it will give me 200% reject, which close to reality?, am i right? or just confusing myself badly?

M

#### Mike_H

I would use total [rejected/(total produced)]x100;

15 produced
5 accepted
10 rejected

reject rate is a % of total production, which in this case would be [10/15]x100 = 66.7%

if you had 15 rejected then reject rate is [15/15]x100 = 100%, which shows reality

(by this definition, you can't reject more that you produce, you can't have a defect rate greater than 100%)

*hope this helps*

J

#### jm1231

Thanks a lot. I got the logic now..... Why I havent think of that! .....

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