What AQL means
AQL stands for Acceptable Quality Limit. It is the worst defect rate, in percent, that the inspection is designed to accept as a process average. AQL 2.5 does not mean "2.5% of your goods are defective". It means the sampling plan is tuned so that lots running at about 2.5% major defects pass most of the time, and lots much worse than that usually fail.
Three levels are used by convention for consumer goods: AQL 0 for critical defects (safety, legal), AQL 2.5 for major defects (the product will not sell or will be returned), and AQL 4.0 for minor defects (cosmetic, a customer would probably not return it).
How many units get checked
The sample size comes from the lot size via the ISO 2859-1 tables (ANSI/ASQ Z1.4 in the US). At General Inspection Level II, single sampling, normal severity:
| Lot size | Sample size | AQL 2.5: accept / reject | AQL 4.0: accept / reject |
|---|---|---|---|
| 281–500 | 50 | 3 / 4 | 5 / 6 |
| 501–1,200 | 80 | 5 / 6 | 7 / 8 |
| 1,201–3,200 | 125 | 7 / 8 | 10 / 11 |
| 3,201–10,000 | 200 | 10 / 11 | 14 / 15 |
| 10,001–35,000 | 315 | 14 / 15 | 21 / 22 |
Read the 3,000-unit row: an inspector pulls 125 units at random, and the lot passes if 7 or fewer have major defects. Seven defective units out of 125 is 5.6% of the sample. That is the risk you accepted when you signed off on AQL 2.5.
What the sample cannot tell you
Sampling catches systematic problems: wrong colour, a stitching fault on every unit, a packaging error. It is weak against rare, scattered defects. If 1% of your 3,000 units have a dead battery, a 125-unit sample has a reasonable chance of finding zero of them and passing the lot with 30 defective units inside.
It also only inspects what is on the checklist. If "charging port accepts cable" is not a check item, nobody tests it. The checklist matters as much as the AQL.
When to pay for a 100% check
- Products with a safety or electrical function where one failure means a recall or a one-star review.
- High unit value: above about $40, the cost of checking every unit is small relative to the cost of a return.
- First order from a new factory, where you do not yet know the process average.
- Orders going straight to Amazon FBA, where a defect rate above 1–2% triggers listing problems and return fees.
- Small lots under 500 units, where the sample is already a large share of the lot.
A 100% inspection for a 2,000-unit order of a simple product typically costs $400–900 in China. The same defects found after arrival cost that per week in returns and lost ranking.
How to read an inspection report
- Check the AQL line and the sample size against the table above. If the sample is smaller than the table says, the result is weaker than claimed.
- Count the defects by category. Seven majors at the limit is a pass on paper and a warning in practice.
- Look at the photos of defects, not only the pass/fail. The type of defect tells you whether it is a process problem or a one-off.
- Confirm the inspected quantity matches the packing list. Inspecting 80% of a finished lot is a different test from inspecting all of it.
Frequently asked
Is AQL 2.5 the right level for Amazon products? +
It is the common default, but for electronics, anything with a safety function or a unit price above $40, we recommend AQL 1.0 for majors or a 100% check. Amazon return rates punish defect rates that AQL 2.5 would pass.
What is General Inspection Level II? +
The standard sampling intensity in ISO 2859-1. Level I samples fewer units, Level III more. Level II is the default unless you specify otherwise.
Does a passed inspection mean the factory is liable for defects? +
Only if your contract says so. The inspection tells you whether to release the final payment; liability for defects found later depends on the warranty terms you negotiated.
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Figures are indicative floor rates and typical fee ranges on our lanes as of Oct 11, 2026. Duty rates depend on your product's tariff code and declared value. This is general information, not customs or legal advice.