How do you calculate cost of poor quality?

Add scrap, rework, warranty, inspection/containment and customer penalties. In the example that is $8,400 + $5,200 + $3,100 + $2,600 + $1,500 = $20,800 for the period.

What is internal vs external failure cost?

Internal failure is defects caught before shipment - scrap plus rework ($13,600 here). External failure is defects that reached the customer - warranty plus penalties ($4,600 here). A high external ratio means your detection is failing.

What is a good COPQ as a percentage of sales?

Average manufacturers sit at 5-15% of revenue; world-class operations run below 5% and sometimes near 2-3%. Track the trend more than the absolute number, since accounting scope varies by plant.

Why does COPQ per unit matter?

It normalizes quality spend against volume so you can compare periods with different output. Here $20,800 over 18,000 shipped units is about $1.16 per unit - a clean KPI to trend month over month.

Is inspection cost really a cost of poor quality?

Yes - appraisal/inspection is money spent because you cannot trust the process to be right the first time. Reducing the need for containment inspection is itself a quality improvement, which is why it belongs in COPQ.

Should prevention costs be in COPQ?

Classic cost-of-quality models include prevention, but this calculator focuses on failure and appraisal spend - the costs you want to drive down. Prevention is the investment you make to shrink these buckets.

Quality calculator

Cost of Poor Quality Calculator

Cost of Poor Quality (COPQ) is the total money a plant loses because things were not made right the first time - scrap, rework, warranty, containment and customer penalties combined. Quality directors and plant managers use it to translate defects into a boardroom-ready dollar figure and to split spend into internal versus external failure. It typically runs 5-15% of revenue in average manufacturers and under 5% in best-in-class ones, so it is a powerful lever for margin. Breaking it into per-unit and failure-type buckets shows exactly where a Six Sigma or containment effort will pay back fastest.

What this calculator does

Combine scrap, rework, warranty, inspection, and customer penalty costs into one quality-loss number.
Use when quality issues need financial priority for corrective action or improvement work.
It adds the five failure-cost buckets into a single COPQ figure, splits it into internal (scrap + rework) and external (warranty + penalties) failure, and divides by shipped units.

Formula used

COPQ = scrap + rework + warranty + inspection + penalties
Internal failure cost = scrap + rework
COPQ per shipped unit = COPQ ÷ shipped units

Inputs explained

Scrap cost: undefined
Rework cost: undefined
Warranty cost: undefined
Inspection / containment cost: undefined
Customer penalties: undefined
Shipped units: undefined

How to use the result

Use it for quarterly quality reviews, cost-of-quality reporting, or to prioritize whether prevention or detection deserves the next investment.
It captures only tangible failure costs; lost customers, brand damage and future orders forfeited to poor quality are real but not included here.

Current U.S. benchmarks

U.S. manufacturing runs at 75.6% of capacity (Federal Reserve, May 2026). New factory orders are up 2.3% year over year (Census).

Common questions

How do you calculate cost of poor quality? Add scrap, rework, warranty, inspection/containment and customer penalties. In the example that is $8,400 + $5,200 + $3,100 + $2,600 + $1,500 = $20,800 for the period.
What is internal vs external failure cost? Internal failure is defects caught before shipment - scrap plus rework ($13,600 here). External failure is defects that reached the customer - warranty plus penalties ($4,600 here). A high external ratio means your detection is failing.
What is a good COPQ as a percentage of sales? Average manufacturers sit at 5-15% of revenue; world-class operations run below 5% and sometimes near 2-3%. Track the trend more than the absolute number, since accounting scope varies by plant.
Why does COPQ per unit matter? It normalizes quality spend against volume so you can compare periods with different output. Here $20,800 over 18,000 shipped units is about $1.16 per unit - a clean KPI to trend month over month.
Is inspection cost really a cost of poor quality? Yes - appraisal/inspection is money spent because you cannot trust the process to be right the first time. Reducing the need for containment inspection is itself a quality improvement, which is why it belongs in COPQ.

Last reviewed 2026-05-12.