Calculate sample sizes and acceptance numbers based on ANSI/ASQ Z1.4 and ISO 2859-1 sampling standards.

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ECQA Free AQL Calculator Online

An AQL Calculator is a tool that automatically determines the required sample size and acceptance criteria for product inspections.

By entering the lot size, inspection level, and AQL values, the calculator provides:

• Sample size code letter
• Sample size
• Acceptance number
• Rejection number

The calculator eliminates manual calculations and helps ensure inspections follow internationally recognized sampling standards.

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How to Use the AQL Calculator

The calculator requires three inputs. After entering the values, it will display the corresponding sampling plan.

1. Lot Size

Enter the total production quantity.

This value determines the sample size code letter based on ISO 2859-1.

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2. Inspection Level

Select the inspection level.

General Inspection Levels:

• General Level I
• General Level II
• General Level III

Special Inspection Levels:

• S1
• S2
• S3
• S4

General Level II is commonly used and provides balanced sampling for most products.

General Level I uses a smaller sample size than General Level II, while General Level III uses a larger sample size.

Special Inspection Levels are commonly used for limited inspections, functional testing, or destructive testing.

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3. AQL Values

Choose the AQL levels for the defect categories: critical, major, and minor.

Examples of common values:

• Critical: AQL 0 is commonly used because safety defects are generally not acceptable. If AQL 0 is not available in the calculator, use the lowest available value to represent a very strict requirement.
• Major: 1.0 to 2.5
• Minor: 4.0 to 6.5

After the inputs are selected, the calculator displays the sample size and the acceptance and rejection numbers for each defect category.

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Example AQL Calculation

A shipment of 2,000 T-shirts is ready for inspection.

Enter:

• Lot Size: 2,000
• Inspection Level: General Level II
• Critical AQL: 0.65
• Major AQL: 2.5
• Minor AQL: 4.0

The calculator displays the required sample size and the acceptance and rejection numbers for the inspection.

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ANSI/ASQ Z1.4 and ISO 2859-1 Calculator

This calculator is based on internationally recognized sampling standards:

• ANSI/ASQ Z1.4
• ISO 2859-1

These standards are widely used in quality control inspections and provide a consistent method for determining sample sizes and acceptance criteria.

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When Should You Use an AQL Calculator?

An AQL Calculator is useful for:

• Pre-Shipment Inspections
• During Production Inspections
• Incoming Quality Control
• Supplier Quality Management
• Factory Audits
• Production Quality Checks

Industries that frequently use AQL sampling include:

• Consumer products
• Electronics
• Toys
• Apparel
• Furniture
• Industrial equipment
• Medical devices
• Automotive components

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Why Use an AQL Calculator?

Save Time

The calculator eliminates manual lookups in AQL sampling tables.

Reduce Errors

Automatic calculations reduce the risk of using incorrect sample sizes or acceptance numbers.

Improve Inspection Consistency

The calculator ensures inspections follow standardized sampling procedures.

Supports Standardized Inspections

The calculator follows internationally recognized sampling standards, helping buyers, suppliers, and inspectors use consistent inspection criteria.

Support Better Quality Decisions

Consistent sampling methods improve communication between buyers, suppliers, and inspection teams.

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Frequently Asked Questions

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Related Resources

New to AQL?

Read our Acceptable Quality Limit (AQL): Complete Guide for Quality Control to learn how AQL sampling works and how to choose the right AQL levels.

Need an AQL reference table?

Download our Free AQL Chart PDF for a printable version of the sampling tables.

Need professional inspection support?

Learn more about our Product Inspection Services and how ECQA can help implement AQL inspections across your supply chain.