Accurate and stable reference standards for calibrating weighing equipment, including variously certified/accredited weights and weight sets from different classes. Products may be constructed of aluminum, stainless steel, brass, iron, and other alloys.

Calibration weights (also known as reference weights or test weights) are manufactured to meet high tolerances and accuracy. They are used to spot-check the performance and verify the calibration of analytical balances, precision balances, and general-purpose scales in research laboratories, educational settings, and other working environments. Some calibration weights may also be used as reference weights for the calibration of improvised or non-certified weights.

How Are Calibration Weights Made?
Calibration weights may be take the form of simple discs, cylinders, wires, or leaves. Sold separately or as sets, they may also be supplied with tweezers, gloves, and a protective case. Calibration weights are often supplied as accessories for specific balance brands and models.

Calibration weights are made from polished brass, aluminum, special stainless steels, or other metals for durability, anti-magnetization, and resistance to corrosion or wear that may affect their accuracy.

Available in nominal values from a few milligrams to 10 kg or more, they may be supplied with certificates or statements of accuracy, compliance, and traceability.

How Are Calibration Weights Classified?
Calibration weights are classified based on accuracy by organizations such as ASTM, OIML, and NIST. The appropriate classification depends on the resolution of the balance and the degree of accuracy needed to satisfy a particular weighing application.

Principal Classes of Calibration Weights:

• Class M1: For standard scales
• Class F1: For precision electronic balances
• Class E2: For highly accurate analytical balances