Information for retailers on what the requirements are when you sell goods by weight or measure and how to comply.

The Weights and Measures Act 1987 and associated regulations set out the rules for selling goods by quantity.

Read Selling Goods by Weight, Measure or Number [PDF, 788 KB] – Trading Standards' guide for business about how to comply with weights and measures laws. You can also download this guide in Chinese [PDF, 658 KB]

Who enforces the rules?

The Ministry of Business, Innovation and Employment's Trading Standards team enforces these rules. Retailers can expect to be visited by a Trading Standards Officer from time to time. They will check that the rules are being followed.

Find out more about Trading Standards' visits.

Weighing goods

Is the weighing or measuring equipment legal?

All weighing and measuring equipment used for selling goods by quantity must be of an approved type. Ask Trading Standards about this. Equipment must be verified by a Trading Standards Officer or Accredited Person. The verification mark can be either a crown or the letters ‘AP’ followed by a number on a seal or sticker.

Remember, check the seal/sticker is still intact after repairs have been made.

Goods weighed in front of customers

When goods are weighed in front of the customer, they must be able to see the actual weighing and the weight.

Is the weighing equipment level and the indicator set to zero?

Regularly check the level bubble on weighing equipment, if one is fitted. Scales can be inaccurate if they are not level. The user must check that the indicator is reading zero before the scale is used.

Deducting the weight of packaging

When selling pre-packed goods or loose goods put into containers e.g. deli pottles, the weight of all packaging must be deducted from the weight sold.

Note: If you do not comply with the above, legal action may be taken against you.

Method of selling

Goods are most commonly sold by weight, measure or by number; either method is acceptable. When goods are sold by weight or measure, the sale must be made in units of the metric system, eg kilograms, grams, litres, millilitres etc.

Pre-packed goods

Pre-packed goods must be sold by net quantity. That means all packaging must be excluded from the quantity charged for.

Pre-packed goods are checked by Trading Standards Officers using the Average Quantity System (AQS) to ensure packages contain their stated amount. The system is designed to give consumers a better assurance that goods packed by weight, measure or number are, on average, correct.

AQS applies to packaged goods that are of the same kind and the same stated quantity e.g. 500g packs of butter. Trading Standards Officers will test 'lots' of packages – that is a group of packages they select when they visit.

Goods that are not packed to the same stated quantity e.g. joints of meat, are not covered by AQS. They will be tested as individual packs, known as 'catch weight goods'.

Ensuring legal compliance

Contact an Accredited Person to test equipment used for weighing or measuring goods. Trading Standards can provide you with contact details of Accredited Persons who can carry out the work you need.

An Accredited Person is a company or individual who has been approved by the Ministry to test weighing and measuring equipment in compliance with weights and measures legislation. He or she will on request issue a certificate of accuracy, valid for 12 months from the date of the test. A current certificate of accuracy will assure consumers that your weighing or measuring equipment has been independently tested.

Keep your certificate of accuracy up-to-date. This may provide you with a defence if a Trading Standards Officer finds your weighing or measuring equipment does not comply with the regulations.

Regularly check the net weight or measure of packaged goods, paying particular attention to in-house packed goods.

Remove any incorrectly weighed goods from sale and isolate them from other stock.

Implement a checking system that includes all of the above points. The system should provide adequate records and be effectively monitored by management.