AQL sampling plan calculator
Enter a lot size, inspection level and AQL for each defect class. The calculator gives the code letter, sample size and Ac/Re, then shows how often the plan accepts lots at each true defect rate, with the OC curve. Critical defects, isolated lots and a printable plan are included. Nothing is sent anywhere.
A free practice tool for factory QC inspectors, intake controllers and supplier technologists who audit incoming packaging, ingredients and finished lots. It comes loaded with case data from Isipho Beverages and Snacks, a fictional plant in Hammarsdale, KwaZulu-Natal, so you can try it without a site of your own.
ISO 2859-1:2026 (3rd edition, 22 January 2026) replaces the 1999 edition and its 2011 amendment. It adds skip-lot inspection, moves OC curves into a method in Annex E, and reworks the tables for usability. The code-letter and Ac/Re values in this tool are from the ISO 2859-1:1999 master tables; confirm against your site’s licensed 2026 copy.
How to use this calculator
- Plan. Pick a case or enter your own lot: lot size, inspection level (level II unless your plan says otherwise), normal inspection, and the AQL for each defect class. Enter the defectives you found to get the decision.
- Probability of acceptance. See how often the plan accepts lots at 1 %, 2 %, 3 % or any rate you choose, and read the OC curve. Compare two plans side by side.
- Critical defects. See what a zero-acceptance sample misses, and why glass, metal, a wrong allergen label or a missing date are controlled by 100 % automated inspection, not by an AQL.
- Isolated lot. For a one-off lot, work from the limiting quality you want to reject.
- Practice with seven lot audits, then Record: print the sampling plan or download it as a spreadsheet.
Outside the table excerpt this tool carries, enter n and Ac from your site’s licensed copy: every probability and chart still works.
// The course behind this tool
Sample what matters, read the plan correctly, and know what a pass does not prove
This calculator comes from Module 2 of the QC Inspector Course for Food and Beverage Manufacturing (FS60-0602). The course covers specifications and defect classes, AQL and micro sampling plans, micro reports and CoAs, calibration and SANS 458 weight control, line clearance, metal detection and X-ray, seals, beverage and heat-treated product checks, holds, rework and CCP records.
This tool stays free. Also free: the Net Content and Weight Control Calculator for the SANS 458 average-quantity rules.