What is DHU
DHU stands for Defects per Hundred Units. It measures the number of defects found in every 100 pieces inspected. DHU is one of the most common quality KPIs in garments and is used by buyers, IE teams, and quality teams to track product quality at the sewing floor, finishing, and final inspection.
How to Calculate DHU
DHU equals number of defects divided by number of units inspected, then multiplied by 100. For example, if 30 defects are found in 500 pieces, DHU is 30 divided by 500 times 100, which is 6.
Practical Example 1 — Sewing Floor
A line produces 800 pieces in a day. The QC team finds 64 defects. DHU is 64 divided by 800 times 100, which is 8. If the target DHU is 5, the line is above target and needs corrective action.
Practical Example 2 — Style Change
A new style has DHU of 12 in the first week, dropping to 6 by the third week as operators gain skill. This trend shows learning curve, and the target DHU of 5 is realistic by the fourth week.
Practical Example 3 — Finishing Section
In finishing, 2000 pieces are checked and 40 defects are found. DHU is 2. Since finishing DHU is usually lower than sewing DHU, comparing both reveals where the majority of defects originate.
Practical Example 4 — Multi-Style Factory
A factory produces 3 styles with DHU values of 4, 6, and 9. Average DHU is not just the arithmetic mean, it must be weighted by pieces produced. The weighted DHU gives the true quality level.
What Causes High DHU
Common causes include poor operator skill, weak inline QC, unclear quality standards, missing pre-production meeting, wrong machine settings, poor fabric quality, high absenteeism, and lack of training. High DHU also increases rework time, which reduces effective capacity.
How to Reduce DHU
Implement inline QC at every 10 to 15 operators. Hold pre-production meetings before every style. Train operators on critical operations. Display defect samples at the workstation. Use poka-yoke where possible. Track DHU daily by operation to find the top defect. Do 5 Why on the top three defects every week. Reward lines that hit DHU targets.
DHU vs Other Quality KPIs
DHU is similar to DPMO (defects per million opportunities) and Defect Rate but expressed in a simpler format. Buyers often use AQL (Acceptable Quality Limit) for final inspection, which is different from DHU. DHU is an internal process indicator, AQL is a shipment acceptance rule.
Common Mistakes
Measuring DHU only at final inspection is too late. DHU must be tracked at each process. Some factories count defects but do not count inspected pieces correctly. Others report DHU only when it is good and hide bad weeks. Good practice is to report DHU honestly every day.
When to Use It
DHU is used daily on the sewing floor, in finishing, and in final inspection. It is part of the daily production meeting and the weekly quality review. IE teams use DHU alongside efficiency and absenteeism to build a full performance picture.