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What this calculator does

This calculator helps you interpret an inspection report that uses AQL sampling.

It estimates:

  • The sample size (n) from lot size and inspection level
  • The accept/reject thresholds (Ac/Re) for Critical, Major, and Minor defects

Then you can check whether the reported defect counts should result in PASS or FAIL.

Why it exists

AQL is not a defect-rate promise. It is a pass/fail rule applied to a sample.

To validate the result in a report, you need:

  • The sample size (n) used for the lot
  • The Ac/Re thresholds used for each defect class

This tool provides those numbers so you can verify the decision.

How it works

1) Enter lot size Inspection level (Level II is common) 2) Select AQL for Critical/Major/Minor 3) Compare findings to Ac/Re
  • PASS if findings ≤ Ac
  • FAIL if findings ≥ Re

Key point: Ac/Re is the allowed number of findings in the inspected sample, not the whole batch.

Standards this is based on

Most AQL sampling used in inspection reports comes from one of these two equivalent systems:

  • ISO 2859-1
  • ANSI/ASQ Z1.4

About MIL-STD-105E

It is a legacy predecessor you still see in older templates.

It does not "apply" as a current standard, but it points to the same family of AQL sampling plans. If you see "MIL-STD-105E" in a spec, treat it as "Z1.4-style AQL sampling" and align on which table/version your inspection firm uses.