Force and Torque Transducer Calibration ISO 376 ISO 7500 EN 12390 ASTM E 74

When the ratio of force applied to a force transducer or a torque meter cannot be accurately determined by means of a calculation, it is necessary to perform a calibration procedure, which consists in establishing the exact ratio between the force (or torque) applied to a dynamometer (or torque transducer) - input - and the electrical signal it releases - output. The operation consists in applying forces that can be accurately measured on a load cell and registering the values provided by the electronic equipment connected to the transducer. This operation is generally performed by applying the protocol established by international standard ISO 376. This standard establishes different accuracy classes. The results of the calibration of a dynamometer lead to the determination of a mathematical polynomial of 2nd or 3rd degree, which allows calculating the value of the force applied to the dynamometer based on the indication provided by the electronic equipment. The formula allowing calculating the level of uncertainty of this value is also part of the calibration.

Calibration procedures used are preferably those acknowledged as accredited by laboratories in force calibration services, according to ISO 17025 Standard (SMB, COFRAC, DKD, UKAS…).

Another application of dynamometers concerns torque and force testing machines meant to characterize the resistance of materials or products. This field is largely covered by standards such as international standard ISO 7500-1, covering uniaxial static tests for metallic materials, or the European standard EN 12390 section 4, dealing with hardened concrete.

As opposed to the dynamometer, there is currently no unified standard that can serve as a guideline for the calibration of torque sensors. However, a calibration guide has been issued by the European Metrology Association EURAMET under reference cg-14 / V.01 dated July 2007, available on the Euramet website.

ISO 6789 International Standard establishes a calibration procedure for dynamometric wrenches.

Two documents drafted by the International Bureau of Weights and Measures (BIPM), are available on their website and constitute the reference on metrology:

  1. The "International vocabulary of metrology – Basic and General Concepts and Associated Terms (VIM)" is available at
    This document is also available from ISO under reference "ISO/CEI Guide 99:2007"
  2. The "Guide to the Expression of Uncertainty in Measurement (GUM)" is available at