AQL Table
Acceptance Quality Limit in AQL Sampling
What Does Acceptable Quality Level (AQL)? How to Read AQL Table?
AQL, or Acceptance Quality Limit, is defined as a “quality level that’s worst tolerance in international standard ISO 2859-1, it’s a statistical tool to inspect a particular sample size for a given lot and set the maximum number of acceptable defects.
In order words, it is the worst tolerable process average when a continuing series of lots is submitted for acceptance sampling.
There are normally three limits chosen, one for critical, major, and minor. Usually, each of these three limits is different for each category, and most Asia exporters are familiar with the type of setting,
AQL was previously known as “Acceptable Quality Level” under earlier editions of the ANSI/ASQ Z1.4 standard, before ISO 2859-1 adopted “Acceptance Quality Limit” as the current standard term., it is an important statistic for companies seeking Six Sigma level of quality control. and the AQL of a product would vary from industry to industry,
AQL sampling is most commonly applied during Pre-Shipment Inspection (PSI), where inspectors use the acceptable quality limit to determine how many units to check before a shipment is approved. Companies dealing with extreme sports equipment or medical tools would have more stringent AQL, as acceptance of defective products could result in health risks.
Please kindly check the sample size and AQL for each inspection by the acceptable quality level calculator as follow
AQL Calculator: Calculate Your Required Sample Size Quickly!
Try our AQL Calculator today and streamline your quality assurance workflow!
Whether you’re managing a manufacturing process, conducting product audits, or ensuring compliance with industry standards, this tool simplifies the process of calculating the required sample size based on the Acceptable Quality Level (AQL).
With just a few inputs, such as Lot size, Inspection Level, and AQL, you can quickly generate accurate results, saving you time and reducing the risk of errors. Perfect for quality control professionals, this calculator ensures that your sampling process aligns with international standards like ISO 2859-1.
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5 Factors Influencing Your Acceptance Quality Limit (AQL) Selection
When determining your AQL sample size for product inspection, it’s crucial to consider the following factors:
1. Target Market Considerations
– Each market has its own AQL standards, so when you manage the quality control system please find out the common AQL for the products in your target market and adapt to it accordingly.
2. Risk Assessment
– The AQL is intrinsically tied to the risk associated with your product. Generally, higher user risk warrants a lower acceptable defect rate. For instance, products with potential severe safety consequences, like pharmaceuticals or aircraft parts, typically have extremely low defect acceptance rates, often below 1%.
3. Development Investment
– Companies heavily investing in product development can aim for lower AQL levels due to the expectation of encountering fewer defective products.
4. Supplier Relationship
– Prior positive experiences with suppliers can support setting lower AQL levels based on established quality performance.
5. Budget Allocation
– Keep in mind that higher AQL levels translate to escalated quality inspection costs. Balancing this against potential losses incurred from defective products is essential.
These factors should guide your decision-making process in arriving at an optimal AQL for your products.
Understanding AQL: Key Terms, Standards, and Defect Classifications
Keywords: AQL Table / ANSI AQL Chart
The standard definition of Acceptance Quality Limit (AQL) is “the maximum defective percent (or the maximum number of defects per hundred units) that, for purpose of sampling inspection, can be considered satisfactory as a process average”.
Keywords: AQL 2.5
When a product defect adversely affects the performance of the product or varies significantly from the specifications, or the defects cause the end customer to return the product, the inspector will the defects to be a “Major”, and the most common AQL inspection assigned to Major defects is 2.5. (Related: What does AQL 2.5 mean in a quality inspection?)
Keywords: AQL 4.0
Typically, minor defects are relatively small or insignificant issues, these issues won’t affect the product’s functionality or form, and customers won’t return the product based on the presence of one or very few minor defects on the product. but AQL 4.0 is typical for the acceptance of minor defects, your goods may fail inspection if the number of minor defects found beyond AQL 4.0
Keywords: Inspection Standard ANSI/ASQ Z1.4 / ISO 2859-1
ANSI/ASQ Z1.4-2003 (R2018): Sampling Procedures and Tables for Inspection by Attributes is an acceptance sampling system to be used with switching rules on a continuing stream of lots for the Acceptable Quality Level specified.
ISO 2859-1: 2026: Sampling procedures for inspection by attributes – Part 1: Sampling schemes indexed by Acceptance Quality Limit (AQL) for lot-by-lot inspection
It provides tightened, normal, and reduced plans to be applied for attributes inspection for percent nonconforming or nonconformities per 100 units.
For the full mechanics of ISO 2859-1 – including the 2026 update and switching rules – see our ISO 2859-1 Practical Guide.
Keywords: Lot size in AQL Chart
The quantity of each product is the lot size, if you ordered different products, then each product considers a separate lot.
Keywords: Three types of defects for consumer goods
Critical Defects:
Totally unacceptable defects, when accepted could lead to harm to the users. or regulations are not respected. AQL inspection requires zero tolerance (AQL c=0)—any critical defect fails the inspection.
Major Defects
Defects that affect functionality or appearance, often leading to customer dissatisfaction, the standard AQL for a major defect is 1.5 or 2.5 (AQL 1.5 or AQL 2.5).
Minor Defects
Defects, which are not likely to reduce materially the usability of the product for its intended purpose but slightly differ from specified standards. most end users won’t mind it. The AQL for minor defects is 4.0 (AQL 4.0)
For how these three defect categories apply specifically to garments, fabric, and sewing, see our AQL Garment Inspection guide.
Keywords: General Inspection level (G-I, G-II, G-III)
Different inspection levels will command different numbers of samples to inspect. General Level II in single sampling plans is the normally used sampling method. (Learn more about What are the General Inspection Levels)
For a deeper walkthrough of choosing and setting inspection levels correctly, see our AQL Inspection Levels Guide.
Keywords: Special Inspection level (S-1, S-2, S-3, S-4)
The special levels can be applied in cases where only a few samples should be checked, mostly the special levels are used only for certain on-site testings, and spot check during container loading supervision.
(Learn more about Special Inspection Levels)
How to use the AQL Table?
A: Determine the Sample Size by Using AQL Table
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a. The AQL Table for Determining Sampling Size
The AQL table will help you to determine the sampling size, we will need to inspect it according to your ordered quantity and your level of severity (G-I, II, or III). The standard level, the one used by default and by 98% of buyers is the General level G-II for a standard AQL inspection.
If your order has multiple references, ideally we should at least inspect a level II on each reference. Indeed, for a standard order, the standard level II from the AQL table gives the minimum sampling size we should check per reference if we do not want to take additional risks.
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b. Sampling Standards for Multiple References
If we inspect a G-II sampling size on multiple reference orders, then the AQL sampling size is diluted and divided by the number of references, increasing the risks as the sampling size must be representative enough.
In order to find the necessary sampling size to be inspected, we look at the first chart and find on the left side the range of items being produced in total.
You have the choice of levels I, II, and III, with Level III being the most stringent testing and level I being the least. As we said above, Level II is the standard and is most often used.
For example below, if you are producing 8000 items, at AQL Chart level II you have the letter L, which in the second table says to inspect 200 items.
- General inspection levels
- L-I
- 80 Pcs
- General inspection levels
- L-II
- 200 Pcs
- General inspection levels
- L-III
- 315 Pcs
- Special inspection levels
- S-1
- 5 Pcs
- General inspection levels
- S-2
- 8 Pcs
- General inspection levels
- S-3
- 20 Pcs
- General inspection levels
- S-4
- 32 Pcs
Another option is you can use our AQL Calculator to find your required sample size from AQL Table
B: Define the Acceptable Quality Limit
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a. Defect Levels and Standards
On the top of the second chart are the defect levels, ranging from 0 to 6.5. You can choose which level to apply for your type of defect: critical, major, and minor. (Learn more about Product inspection standards)
Usually, most importers will choose standard defect levels which are 0/2.5/4.0 but one can choose 1/1/1 if he wishes or 0/1.5/2.5 like in the automotive industry.
Using the standard 0/2.5/4.0 defect levels and a sample size of 200, we see that if you have more than 0 critical defects, 10 major defects, or 14 minor defects, you should reject your shipment. Of course, the decision about what to do after you received the inspection reports belongs to you, inspection only can give suggestions.
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b. Importance of AQL in Quality Assurance
So most importers will put AQL sampling into the purchase contract and inspection checklist to avoid any misunderstanding in production, suppliers will be clear with your quality requirements. Importers will also wish to discuss all inspection findings with their vendor/manufacturer in order to improve whatever possible. In case the inspection results are very close to AQL limits, it is vital that you double-check if the AQL of found defects is acceptable to you or not.
Check the below chart of defect findings to better understand the acceptable quality limits
- Sample Size
- AQL
- K-125pcs
- L-200pcs
- G-II AQL 0/1.5/2.5
- 0
- 0 Pcs
- 0 Pcs
- Sample Size
- 1.5
- 5 Pcs
- 7 Pcs
- Sample Size
- 2.5
- 7 Pcs
- 10 Pcs
- G-II AQL 0/2.5/4.0
- 0
- 0 Pcs
- 0 Pcs
- Sample Size
- 2.5
- 7 Pcs
- 10 Pcs
- Sample Size
- 4.0
- 10 Pcs
- 14 Pcs
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