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                               Calibration Weights


Calibration Weights are certified to be used to ensure that scales or balances are giving you accurate readings. Calibration weights are assigned a class which is based on the accuracy or tolerance of the weight.

OIML: The Organisation Internationale de Métrologie Légale or International Organization of Legal Metrology (OIML) is an intergovernmental organization that provides standards and systems with the goal of harmonizing legal metrology procedures. From lowest (most accurate) to highest tolerance, OIML has classified the Calibration Weights in accuracy classes as E1, E2, F1, F2, M1, M2, and M3.

Tolerance Levels

The following tables shows the tolerance levels for the different classes of weights, as per OIML.:

5000 kg  25000800002500008000002500000
2000 kg  10000300001000003000001000000
1000 kg 160050001600050000160000500000
500 kg 800250080002500080000250000
200 kg 300100030001000030000100000
100 kg 160500160050001600050000
50 kg25802508002500800025000
20 kg10301003001000300010000
10 kg5165016050016005000
5 kg2.58.025802508002500
2 kg1310301003001000
1 kg0.51.651650160500
500 g0.
200 g0.10.31.031030100
100 g0.
50 g0.
20 g0.0250.
10 g0.0200.
5 g0.0160.
2 g0.0120.
1 g0.0100.
500 mg0.0080.0250. 
200 mg0.0060.0200. 
100 mg0.0050.0160. 
50 mg0.0040.0120.040.120.4  
20 mg0.0030.0100.0300.100.30  
10 mg0.0030.0080.0250.080.25  
5 mg0.0030.0060.0200.060.20  
2 mg0.0030.0060.0200.060.20  
1 mg0.0030.0060.0200.060.20  

Certifications of Weights

While browsing Calibration Weights, you might come across mentions of certifications. Indeed, depending on your application, you may require that your calibration weights come with a certificate confirming that the lab testing the weights is accredited.

ISO/IEC 17025: The International Organization for Standardization (ISO) is an independent non-governmental organization comprising a membership of 164 national standards bodies. The International Electrochemical Commission (IEC) is an international standards organization for electrotechnical fields. Together with other liaison organizations, they created the ISO/IEC 17025 standards. This is the international reference to be used by testing and calibration laboratories that want to display their ability to provide reliable results.

Calibration Weights 1 4a
Calibration Weights 1 4b
Calibration Weights 1 4c