The Acceptance Quality Limit (AQL) is used in product inspections to determine the maximum acceptable number of defective items in a sample batch. If the number of defective items is higher than the maximum acceptable limit, the batch is rejected.
AQL is typically set differently for minor, major, and critical defects. Since critical defects are unacceptable, AQL for critical defects is commonly 0. In sampling inspections, TradeAider inspectors follow the ISO 2859 standard, which forms the basis for the Acceptable Quality Limit (AQL) methodology. The standard provides tables to determine sample sizes and defect thresholds, ensuring precise and reliable quality assessments.
Our inspectors use pre-defined sampling plans to perform a detailed analysis of production samples, verifying whether they meet the AQL. Our transparent, AQL-based approach to sampling inspections helps you make informed decisions on whether to accept or reject an entire batch.
Benefits of Using AQL
Inspecting a sample of products from a batch in a consistent and systematic way, instead of testing every single item, provides significant benefits
Cost-Effective
Inspect only a sample, not every item, reducing time and expense.
Reliable Standards
Based on ISO 2859-1, AQL is trusted worldwide for consistent quality.
Risk Management
Catch defects early to avoid costly recalls or customer complaints.
Flexibility
Adjust AQL levels to match your product's risk and market needs.
How to Pick Your Sample Size and Defect Limit
Determining how many items to check and how many flaws are okay can seem daunting—but we've got your back. Our experts will help you select the ideal inspection level and AQL value tailored to your needs. Better yet, our AQL Sampling Simulator lets you see it all in action and grasp the process firsthand. Here's a simple example:
If you need to inspect 2,000 LED lamps using a normal inspection (Level II with an AQL of 2.5), simply enter the relevant data into the designated fields in the AQL calculator below:
Quantity
2000
Inspection level
General Inspection II
AQL
2.5
The simulator will quickly reveal your sample size (e.g., 125 LED lamps) and the maximum defects allowed (e.g., 7) before rejecting the batch.
Give it a go—it's that easy!
How to read the AQL table?
There are basically two tables. We can classify a product into three AQL levels: critical defects, major defects, or minor defects. First, the sample size is determined based on the total batch size. The sample is then inspected for defects, which are categorized as critical, major, or minor. Using the AQL tables (Table A and Table B below), inspectors find the acceptable number of defects for each type. You can also use an AQL simulator, like ours above, to do the task for you.
Table A: Sample size code letters
The most commonly used standard is the AQL Table A (below) which is used as a fundamental tool when carrying out quality control inspections. The AQL Table makes it easy for the buyer, manufacturer and quality control provider to come together in agreement on quality inspection standards. This table contains rows for various batch sizes and columns for the different inspection levels. By finding where your batch size and inspection level intersect, you can determine the code letter. Find the respective Lot Size (quantity) and general inspection level: Code letter L Note: The AQL tables below are based on the ANSI/ASQ Standard Z1.4 – 2008.
Table B: Single sampling plans for normal inspection
Once you know the code letter, you can then move on to table 2. This table tells you the sample size based on the code letter you obtained from Table 1. Table 2 includes single sampling plans for normal inspections and the check marks on the table show how many products have passed whereas, the cross shows how many have failed. The up arrows mean you should use the sample size listed above the arrow. If the arrow matches or is bigger than your batch size, you should do a 100% inspection or a piece-by-piece inspection. For down arrows, use the first sample size listed below the arrow. Locate Row L (the required sample size of 200) In compliance with AQL 2.5, no more than 10 units from a sample size of 200 may fail the inspection.
AQL Chart
In performing sampling inspection, TradeAider inspectors exclusively apply the ISO 2859 standard and the tables provided by it.
