What Does Legal for Trade Mean?

Legal for trade: Weighing up the requirements

In all commercial applications where product is sold by weight, it is a legal requirement that weighing equipment must be verified as ‘legal for trade’ or ‘trade approved’. In summary, this means that the equipment (from an individual scale to a complete pre-pack line) has undergone a stringent set of tests to ensure it is sufficiently accurate and fit for purpose.

If a trade approved unit undergoes any alteration or repair, it will require re-verification. This then ensures that the approval remains valid.

The following list provides examples of typical applications where a legal-for-trade scale might be required:

Antique scale.

Who governs this law?


Weights and measures authorities around the world are responsible for controlling legal for trade equipment and related legislation. Most countries globally (outside of the USA) have also adopted International Organization of Legal Metrology (OIML) requirements for weighing equipment. OIML has developed a set of international guidelines relating to the manufacture and use of weighing and measuring instruments for legal metrology applications.

Canada Specific

In Canada, approval for trade is also governed by standards and testing by Industry Canada under Measurement Canada’s approval process. Measurement Canada approval is required even if the product is NTEP certified.

Please click here to see more about recent changes to Measurement Canada’s Weights and Measures Regulations

This certification can also only be given by a weights and measures inspector or an ‘approved qualifier’. An appropriate approved body must evaluate the design and operation of the equipment to ensure that it conforms to the published guidelines/ requirements.  It is also an offence to have, or use, seriously incorrect equipment or to alter equipment that is incorrect after it has been stamped.

International Organization of Legal Metrology (Global)


National Conference for Weights and Measures: NTEP (USA)


Measurement Canada


*Disclaimer: This document is intended to provide a basic introduction, it is by no means an exhaustive explanation of the regulations and should not be used as such. Those needing to fully understand the how the law impacts upon their business should refer to the links outlined in the ‘useful links’ section of this page, or speak to one of our sales representatives.