AQL ChartAQL sampling calculator
Enter the lot size, choose an inspection level and an AQL for each defect class. You get the sample size code letter, the sample size, and the accept and reject numbers for single sampling under normal inspection.
Sampling plan
- Code letter
- L
- Sample size
- 200
- Lot size range
- 3,201–10,000
| Defect class | AQL | Sample size | Accept up to (Ac) | Reject from (Re) |
|---|---|---|---|---|
| Major defects | 2.5 | 200 | 10 | 11 |
| Minor defects | 4.0 | 200 | 14 | 15 |
- Code letter L corresponds to a sample of 200.
Single sampling, normal inspection. Table values are transcribed from MIL-STD-105E (public domain), the standard from which ANSI/ASQ Z1.4 and ISO 2859-1 descend.
How the result is read
Lot size and level give a code letter
Table I maps the lot size and the inspection level to a sample size code letter. Level II is the one normally used; S-1 to S-4 keep samples small.
Code letter and AQL give the plan
Table II-A gives a sample size for the letter and, under each AQL, an acceptance number (Ac) and a rejection number (Re). An arrow means: use the first plan below or above it, with that row’s sample size.
Count and compare
Inspect the sample. If the number of defective units is Ac or fewer, the lot is accepted; if it is Re or more, the lot is rejected.
AQL chart for general inspection level II
Sample size and accept/reject numbers by lot size for six AQLs from 0.65 to 6.5. Where the table has an arrow, the cell shows the plan the arrow leads to and its sample size.
| Lot size | Code letter | Sample size | AQL 0.65Ac / Re | AQL 1.0Ac / Re | AQL 1.5Ac / Re | AQL 2.5Ac / Re | AQL 4.0Ac / Re | AQL 6.5Ac / Re |
|---|---|---|---|---|---|---|---|---|
| 2–8 | A | 2 | 0 / 1↓ F · n = 20 | 0 / 1↓ E · n = 13 | 0 / 1↓ D · n = 8 | 0 / 1↓ C · n = 5 | 0 / 1↓ B · n = 3 | 0 / 1 |
| 9–15 | B | 3 | 0 / 1↓ F · n = 20 | 0 / 1↓ E · n = 13 | 0 / 1↓ D · n = 8 | 0 / 1↓ C · n = 5 | 0 / 1 | 0 / 1↑ A · n = 2 |
| 16–25 | C | 5 | 0 / 1↓ F · n = 20 | 0 / 1↓ E · n = 13 | 0 / 1↓ D · n = 8 | 0 / 1 | 0 / 1↑ B · n = 3 | 1 / 2↓ D · n = 8 |
| 26–50 | D | 8 | 0 / 1↓ F · n = 20 | 0 / 1↓ E · n = 13 | 0 / 1 | 0 / 1↑ C · n = 5 | 1 / 2↓ E · n = 13 | 1 / 2 |
| 51–90 | E | 13 | 0 / 1↓ F · n = 20 | 0 / 1 | 0 / 1↑ D · n = 8 | 1 / 2↓ F · n = 20 | 1 / 2 | 2 / 3 |
| 91–150 | F | 20 | 0 / 1 | 0 / 1↑ E · n = 13 | 1 / 2↓ G · n = 32 | 1 / 2 | 2 / 3 | 3 / 4 |
| 151–280 | G | 32 | 0 / 1↑ F · n = 20 | 1 / 2↓ H · n = 50 | 1 / 2 | 2 / 3 | 3 / 4 | 5 / 6 |
| 281–500 | H | 50 | 1 / 2↓ J · n = 80 | 1 / 2 | 2 / 3 | 3 / 4 | 5 / 6 | 7 / 8 |
| 501–1,200 | J | 80 | 1 / 2 | 2 / 3 | 3 / 4 | 5 / 6 | 7 / 8 | 10 / 11 |
| 1,201–3,200 | K | 125 | 2 / 3 | 3 / 4 | 5 / 6 | 7 / 8 | 10 / 11 | 14 / 15 |
| 3,201–10,000 | L | 200 | 3 / 4 | 5 / 6 | 7 / 8 | 10 / 11 | 14 / 15 | 21 / 22 |
| 10,001–35,000 | M | 315 | 5 / 6 | 7 / 8 | 10 / 11 | 14 / 15 | 21 / 22 | 21 / 22↑ L · n = 200 |
| 35,001–150,000 | N | 500 | 7 / 8 | 10 / 11 | 14 / 15 | 21 / 22 | 21 / 22↑ M · n = 315 | 21 / 22↑ L · n = 200 |
| 150,001–500,000 | P | 800 | 10 / 11 | 14 / 15 | 21 / 22 | 21 / 22↑ N · n = 500 | 21 / 22↑ M · n = 315 | 21 / 22↑ L · n = 200 |
| 500,001 and over | Q | 1,250 | 14 / 15 | 21 / 22 | 21 / 22↑ P · n = 800 | 21 / 22↑ N · n = 500 | 21 / 22↑ M · n = 315 | 21 / 22↑ L · n = 200 |
- ↓use the first sampling plan below the arrow
- ↑use the first sampling plan above the arrow
- Ac = acceptance number
- Re = rejection number
If the sample size equals or exceeds the lot or batch size, do 100 percent inspection.
Sample size code letters (Table I) · Single sampling plans for normal inspection (Table II-A)
Short guides
- How to choose an inspection level: I, II, III and S-1 to S-4
What the seven inspection levels do, in the words of the sampling standard: level II is the normal one, I and III trade discrimination for sample size, and S-1 to S-4 keep samples small at a higher risk.
- How to read an AQL table, step by step
Reading an AQL table in three steps: lot size and inspection level to a code letter, code letter and AQL to a sample size with Ac and Re, and what to do when you land on an arrow.
- What AQL 2.5 means, with the numbers from the table
AQL 2.5 read from the table: the sample size, acceptance number and rejection number for every lot size at general inspection level II, and what the 2.5 does and does not promise.
- What is AQL? The definition in the sampling standard
What AQL means in acceptance sampling, read from the definition in MIL-STD-105E: a limit on the process average over a series of lots, not a promise about any single lot.
Questions about the table
- What do Ac and Re mean?
- Ac is the acceptance number: the largest count of defective units in the sample at which the lot is still accepted. Re is the rejection number: the count at which the lot is rejected. In this table Re is always Ac + 1.
- What do the arrows in the table mean?
- A down arrow means use the first sampling plan below the arrow; an up arrow means use the first sampling plan above it. The sample size then comes from the row where the plan is found, not from the original code letter.
- What if the sample size is larger than the lot?
- The table footnote says: if the sample size equals or exceeds the lot or batch size, do 100 percent inspection.
- Which standard do the numbers come from?
- From Table I and Table II-A of MIL-STD-105E (1989), a United States Government publication in the public domain. ANSI/ASQ Z1.4 and ISO 2859-1 are the current standards that descend from it. Check the edition your contract names.
Source and limits
Values on this site are transcribed from MIL-STD-105E, Sampling Procedures and Tables for Inspection by Attributes (U.S. Department of Defense, 10 May 1989), Tables I and II-A. Every cell was read from the page scans and then compared by script with a second, separately keyed copy of the tables.
This is a reference tool. It covers single sampling under normal inspection only — not tightened or reduced inspection, and not double or multiple sampling. It has not been compared cell by cell with the current paid editions of ANSI/ASQ Z1.4 or ISO 2859-1. The standard named in your contract or purchase order, in the edition it names, is what governs.
Tables checked 11 October 2026 · Download the tables as JSON · MIL-STD-105E page scans (Internet Archive)