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Buying and selling goods and services by weights and other measures

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Trade measurement laws regulate retail and wholesale transactions where you determine the price by measurement.

Consistency and certainty in measurement supports fair and open competition. It makes all businesses, regardless of their size or financial strength, follow the same rules.

Confidence in accurate measurement:

  • helps consumers and businesses make informed purchasing decisions
  • supports the efficient operation of the market
  • reduces disputes and lowers transactions costs in commercial dealings
  • provides a sound evidential basis for legal and regulatory measurements

Australia’s trade measurement laws support confidence in accurate measurement by ensuring that:

  • measuring instruments are fit for purpose
  • measurements are made correctly
  • representations about measurements are accurate

The National Measurement Institute (NMI) administers laws that cover:

Complying with trade measurement laws

You must comply with these laws if you:

  • buy or sell goods or services by measurement (e.g. selling meat, buying gold or transporting freight by weight)
  • manufacture, pack, import or sell pre-packaged goods
  • supply or maintain measuring instruments used for trade

The laws apply to both wholesale and retail businesses. 

Manufacturers, packers, importers and retailers must ensure all batches of pre-packaged articles meet the legislative requirements for correct measurement. This includes requirements for the position, size and format of measurement labels. It also includes requirements for the type and units of measurement to be used on labels for specific products. This is usually weight or volume but can also be number or linear or area measurement.

Read the Guide to the Sale of Pre-Packaged Goods for more information.

Find out more specific information relating to the type of goods you sell:

Measuring instruments

If you use a measuring instrument—such as a scale—to determine the price when buying or selling goods and services, you must make sure the instrument is:

  • an approved type, that is suitable for its intended purpose
  • verified before use by a licensed technician or inspector
  • used in the correct manner (e.g. level and indicating zero before use)
  • kept clean and in good working order
  • verified after each repair or adjustment

Measuring instruments used for trade include:

  • scales to determine the weight when selling meat or buying gold
  • rulers to measure the length when selling fabric
  • petrol pumps to measure the volume when selling fuel

We recommend you have your measuring instruments used for trade checked regularly by a technician licensed by NMI (servicing licensee).

For a list of servicing licensees, email

Approval of measuring instruments 

If you use a measuring instrument for trade, its design must have NMI approval. You can ask if measuring instruments have NMI approval before you buy them. 

Find out more about pattern approval.

Verifying measuring instruments

If you use a measuring instrument for trade, you must make sure it has been verified by a servicing licensee before using it. To find a servicing licensee near you, email

Regulating trade measurement

NMI employs trade measurement inspectors who can visit a place of business at any reasonable time of day. This may be in response to a complaint or enquiry from a consumer, or as part of a trade measurement compliance inspection program. 

Find out more about our compliance activities from our:

As the national trade measurement regulator we aim at all times to provide high quality service. The Legal Metrology Service Charter is our public commitment to customers and stakeholders on what you can expect from us in service standards and delivery.

Tips for consumers

  • Check the quantity statements on the goods you buy.
  • Make sure you have a clear view of the scales. When buying goods by weight over the counter, the trader must place the scales so you can see the weight, price per kilogram, total price and the goods being weighed. If not, they should provide you with a written statement of the measurement.
  • Ensure the shop scales display zero weight before the trader weighs your goods. 
  • Make sure that the scale is clear of other items and the trader only weighs the goods you are purchasing when they calculate the price.
  • Check the price per kilogram on the scales matches the advertised price.
  • Check the total price on the scales is the price the trader charges you at the checkout.
  • Check your receipt to ensure the calculated price matches the advertised price.
  • Pay only for the product, not the packaging material. In many stores, traders set the electronic checkout scales to automatically deduct the weight of the packaging during the weighing process. In other stores, staff manually set the scale to deduct the weight of the packaging materials.
    For example, when you buy apples in a plastic bag, you should only pay for the apples. If you buy potato salad at the deli counter, you should only pay for the salad, not for the weight of the plastic container.
  • If you are not present during the measuring of the goods, ensure you have a receipt that states the measurement used.
  • At the service station, after you have picked up the nozzle and before you start filling your fuel tank, make sure the display of the fuel dispenser is indicating all zeroes on the volume and total price indicators.

Read more 

Contact us

To find out more about trade measurement laws or report a suspected breach contact the trade measurement helpline:

Last updated: 13 September 2019

Content ID: 52623