Find practical AQL sample sizes for incoming inspections. Estimate accept and reject limits fast. Keep decisions consistent across every production batch.
| Lot size | Level | AQL (%) | Code | n | Ac | Re |
|---|---|---|---|---|---|---|
| 80 | II | 2.500 | E | 13 | 0 | 1 |
| 400 | II | 1.000 | H | 50 | 0 | 1 |
| 2500 | II | 0.650 | K | 125 | 0 | 1 |
| 15000 | III | 0.400 | N | 500 | 2 | 3 |
| 200000 | I | 4.000 | M | 315 | 12 | 13 |
AQL planning starts with lot size because it drives the code letter and nominal sample size. Inspection Level II is a common default; Level I reduces sample size for stable, low‑risk processes; Level III increases sample size when risk is higher. With the same AQL, moving from Level I to III typically increases n, improving sensitivity to defects. This calculator shows the chosen code letter and resulting sample size so you can plan staffing, time, and inspection capacity.
AQL is a percent and is best viewed as a long‑run quality target, not a guarantee for every lot. At AQL 1.0%, the planning expectation is about 1 defect per 100 units. The calculator converts that target into an expected defect count using n × (AQL/100). Running several AQL values side‑by‑side helps you see how “minor” and “major” defect targets change the decision rule quickly.
Sampling decisions use acceptance (Ac) and rejection (Re) numbers. A practical approximation is to accept when observed defects are ≤ Ac and reject when defects are ≥ Re. The calculator uses Ac = floor(expected defects) and Re = Ac + 1, which creates clear thresholds without over‑promising precision. Example: if n = 200 and AQL 1.0%, expected defects are 2.0, so Ac = 2 and Re = 3.
Every plan trades off producer risk (rejecting good lots) and consumer risk (accepting poor lots). A tighter AQL or higher inspection level improves customer protection but raises inspection cost and may increase false rejects. Many programs set different AQLs for critical, major, and minor defect classes to match business impact.
Records should capture lot size, inspection level, AQL, sample size, defects found, and the final decision. CSV export supports attaching results to batch paperwork, while PDF output standardizes reports for audits. Include inspector ID, date, and any rework disposition to improve traceability. If your contract mandates a formal standard table, use this calculator for planning and verify the final Ac/Re values against the approved tables.
It returns a planning-style code letter, sample size, and approximate acceptance and rejection numbers based on your lot size, inspection level, and AQL target. Use it to compare scenarios before running an inspection.
No. Use it for fast planning and documentation drafts. If your customer contract or QMS requires a specific standard table, confirm the final sample size and Ac/Re values from the approved reference.
Level II is a common baseline. Choose Level I when the process is proven and risk is low, and Level III when the product is high risk, supplier history is weak, or you need stronger detection.
The tool estimates expected defects as n × (AQL/100). It then sets Ac to the floor of that value and Re to Ac + 1, creating simple thresholds that are easy to apply during inspection.
Yes. Run the calculator once per defect class, record the chosen AQL, and keep separate defect counts. This keeps decision rules aligned with the severity of issues and avoids mixing acceptance criteria.
Include lot ID, lot size, inspection level, AQL, sample size, observed defects, decision, date, and inspector. Add any rework or containment notes so reviewers can trace how the disposition was reached.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.