Scale Calibration Weights & Test Weights for Scales
Calibration weights—also referred to as test weights or check weights—are precision reference masses used for scale calibration and routine accuracy verification. Selecting the correct calibration weight class ensures reliable measurements, regulatory compliance, and consistent performance across industrial, laboratory, and commercial weighing applications.
How to Choose the Right Calibration Weights
Use the checklist below to quickly identify the best weights for your scale or balance:
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Match the weight tolerance to your scale’s readability (a common guideline is tolerance ≤ 1/3 of scale readability).
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Select the appropriate class of calibration based on accuracy requirements and regulatory needs.
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Choose materials suited to your environment, such as stainless steel for corrosion resistance or cast iron for rugged industrial use.
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Determine whether you need certified calibration weights with traceability documentation or general-purpose check weights for routine testing.
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Consider complete calibration weight sets for faster, multi-point scale checks.
Calibration Weight Classes & Standards
Calibration weights are manufactured to recognized national and international standards to ensure accuracy and repeatability.
ASTM Calibration Weights
ASTM International standards are commonly used in the United States for commercial and industrial scale calibration. These classes support routine testing, verification, and quality control programs across many industries.
OIML Calibration Weights
The International Organization of Legal Metrology (OIML) establishes global weight classes used in laboratory and high-accuracy applications. Common OIML classes include:
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Class E2 – High-precision reference standard weights for laboratory balances
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Class F1 – Precision calibration and verification of high-resolution scales
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Class F2 – General precision work and routine scale calibration
Choosing the correct standard and class helps ensure your calibration process meets internal quality requirements and external audit expectations.
Types of Test Weights
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Grip Handle Weights
Grip handle weights feature built-in handles or grips that make them easy to handle and transport. These weights are commonly used in industrial settings for calibrating scales and testing material handling equipment. Grip handle weights are available in various shapes and sizes, with the handles designed for ergonomic comfort and ease of use.
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ASTM Class Weights
ASTM Class weights are precision weights that meet specific standards set by the American Society for Testing and Materials (ASTM). These weights undergo rigorous testing and certification processes to ensure accuracy and consistency. ASTM Class weights are available in various classes, ranging from Class 0 (the highest accuracy) to Class 7 (the lowest accuracy), depending on the intended application and calibration requirements.
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Cast Iron Weights
Cast iron weights are commonly used for heavy-duty industrial applications due to their durability and resistance to wear and tear. These weights are often used for testing and calibrating industrial scales and heavy-duty weighing equipment. Cast iron weights are available in various shapes and sizes, including cylindrical, rectangular, and slotted designs.
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Analytical Weights
Analytical weights are precision weights used for calibrating analytical balances and precision weighing instruments. These weights are manufactured with the highest level of precision and accuracy, often with tolerance levels down to micrograms or milligrams. Analytical weights are typically made from materials such as stainless steel or aluminum and are handled with extreme care to prevent contamination or damage.
Applications & Industries
Calibration and test weights are used across a wide range of environments, including:
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Industrial manufacturing and production facilities
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Laboratory, research, and quality assurance departments
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Shipping, receiving, and warehouse operations
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Food, pharmaceutical, and chemical processing
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Educational and training laboratories
Each application may require different weight classes, materials, and certification levels.
Frequently Asked Questions
What is the difference between calibration weights and check weights?
Calibration weights are used to adjust and verify scale accuracy, while check weights are typically used for routine testing to confirm ongoing performance between calibrations.
What class of calibration weight do I need?
The correct class depends on your scale’s readability, application, and regulatory requirements. Higher-precision balances generally require OIML E2, F1, or F2 weights, while industrial scales often use ASTM classes.
Do I need certified calibration weights?
Certified weights with traceability documentation are recommended for regulated environments, audits, and formal quality programs.
How often should scales be tested with calibration or test weights?
Testing frequency depends on usage, environment, and compliance requirements, but many facilities perform routine checks daily, weekly, or monthly.
Need Help Selecting Calibration Weights?
If you’re unsure which scale calibration weights or test weights for scales are right for your application, our team can help you choose the correct classes, materials, and weight sets. Contact American Scale Supply for expert guidance and dependable weighing solutions.