AQL sample size calculator
Find the sample size for a lot under ANSI/ASQ Z1.4 acceptance sampling, general inspection level II.
Track inspection results
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How it is calculated
The lot size sets the code letter from Z1.4 Table I (general inspection level II). The code letter gives the sample size: A 2, B 3, C 5, D 8, E 13, F 20, G 32, H 50, J 80, K 125, L 200, M 315, N 500, P 800, Q 1250.
Worked example
Lot of 1000 units: code letter J, sample size 80.
Steps
- Enter the lot size.
- Read the code letter and sample size.
- Take that many units at random, then use the AQL table to find the accept and reject numbers.
Frequently asked questions
Does this give the accept number?
No. The accept and reject numbers come from Z1.4 Table II-A, which depends on the AQL you choose. This calculator gives the sample size only.
What is general inspection level II?
The default level in Z1.4. Use level I for less discrimination, or level III for stricter inspection.
Is this for tightened or reduced inspection?
This covers normal inspection. Switching rules are in Z1.4 section 9.
Related calculators
References
ANSI/ASQ Z1.4 (sampling procedures and tables for inspection by attributes), Table I, general inspection level II.
Estimates for information only. Verify critical values with a qualified engineer or your supplier standards.