Calibration Masses for Balances

With more sophisticated testing and more frequent auditing of laboratory equipment, it has become increasingly necessary for laboratories to calibrate their own balances. Gilson Calibration Masses are offered to check span and linearity and calibrate electronic balances.


The commonly used Span Calibration method uses one-point calibration with a single mass approximately equal to the capacity of the balance. Some balances use the Linearity Calibration method which allows the user to select multiple mass settings, normally defined as zero, center (half span), and full span of the balances capacity. This method minimizes deviation throughout the balance's weighing range.

Gilson offers Calibration Masses in ASTM Classes 1 and 4, NIST Class F and Ultra Class. Ultra Class weights boast weight tolerances 40—50% tighter than ASTM Class 1 and equal to or exceeding OIML Class E2. Ultra Class and ASTM Class 1 masses are highly polished stainless steel. ASTM Class 4 weights are satin-finished stainless steel. Recessed grip handles are part of the 10kg and 20kg weights for easier handling and stacking. Individual weights from 10—4,000g include a glove and protective, foam-lined plastic case. Optional cases for 10kg and 20kg weights are high-impact plastic, reinforced with metal edges, please inquire.

Precision Mass Sets are available in Ultra Class, ASTM Class 1 and ASTM Class 4 with ranges of 1mg—100g and 1—100g. Weights are supplied in 5-2-2-1 series as ASTM E 617 specifies.

NIST Class F Calibration Masses are available for higher capacity balances and scales. Fabricated of cast iron with integral grip handles. Traceable or NVLAP Certificates are available for all masses and sets.

Traceable Certificates document traceability to NIST and compliance with ASTM or OIML specifications. They include nominal value and correction, date of calibration, accuracy class, customer name and purchase order number. NVLAP Weight Calibration Certificates should be requested by users who must provide certification to ISO, FDA, ANSI or other requirements. Report format and contents comply with NVLAP requirements. Order masses or sets with these certifications, by adding "T" for Traceable certificate or "W" for NVLAP Certificate to the catalog number.