Free AQL Sampling Calculator - ANSI/ASQ Z1.4
Major Defects
Minor Defects
Sample Reports
Review anonymized inspection report excerpts with defect classifications and on-site photos.
Inspector Videos
Follow our inspectors through carton opening, testing and packing verification.
Client Reviews
17+ years of QC experience serving global brands, retailers and trading companies.
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What is AQL?
AQL (Acceptable Quality Limit) is the core metric of the ANSI/ASQ Z1.4 and ISO 2859-1 acceptance sampling systems. It represents the worst tolerable process average that will still allow a lot to be accepted. For example, AQL 2.5 means that when a supplier's actual defect rate is 2.5% or lower, the sampling plan will accept the lot with high probability.
Normal vs Tightened/Reduced
This calculator uses single normal inspection. Switch to tightened inspection when lot quality is unstable (stricter Ac/Re) or reduced inspection when quality is consistently good (smaller sample size).
Major vs Minor Defects
Major defects affect function, safety or regulatory compliance; Minor defects are cosmetic or usability issues that do not affect function. Major AQL is usually lower than Minor AQL.
Why On-Site Inspection Still Matters
第三方产品检验能确保抽样真正随机、判定标准统一、报告可追溯。">AQL tells you how many to inspect and how to decide, but random sampling, testing methods and defect classification still require a trained inspector on site. Third-party product inspection ensures true randomness and consistent standards.
How to Use This Calculator
- Select the Lot Size range closest to your order quantity.
- Choose the Inspection Level; General II is the default for most consumer goods.
- Set the Major AQL and Minor AQL separately; Major is usually stricter.
- Click Calculate to see sample size, Ac, Re and a plain-language explanation.
Tip: Share a specific result via URL parameters, e.g. ?lot=1201-3200&level=II&major=2.5&minor=4.0.