Normal · single sampling

AQL Calculator

Calculate the sample size and acceptance / rejection numbers for a normal single-sampling plan. Start with your lot size, inspection level and agreed AQL.

Normal · single sampling

Your sampling plan

Code letterL

Units to inspect200

Acceptance number · Ac10

Rejection number · Re11

5,000 · II · AQL 2.5

For this defect class, accept at 10 or fewer nonconforming units; reject at 11 or more. Other checks and classes still apply.

For counting nonconforming units. AQL 2.5 is not a promise that 97.5% of the lot conforms.

Discuss your requirements

Read the result correctly

The table may change the sample size

A code letter does not always mean its nominal sample size. The calculator follows the table direction for the selected AQL and shows the resulting sample.

When the plan reaches the whole lot

Inspect all units. The tool then hides sample-based Ac/Re; agree the full-inspection acceptance rules with your buyer.

Agree critical-defect rules separately

A zero-acceptance policy is not an AQL value of zero. Define defect classes, safety checks and escalation rules before inspection.

Scope & standard editions

This tool uses the normal single-sampling lookup used by TTSQC. It does not implement switching rules, tightened or reduced inspection, double sampling or skip-lot inspection. Confirm the contractual standard and edition before using a plan for an order.

ISO 2859-1:2026 is the current published edition. This calculator is not a substitute for the licensed standard or a validation against that edition.

Reference standards: ISO 2859-1 ↗ · ANSI/ASQ Z1.4 ↗

AQL is not a product pass rate