Scales

People weigh things for all sorts of reasons. A baker weighs flour for a cake. Someone posting a parcel weighs it before they pay. A stallholder weighs cheese or apples for a customer.

At home, a scale only has to suit the cook. Once someone sells by weight, the law has a say in the scale they use.

Selling by weight

The Office for Product Safety and Standards (OPSS) sets this out on GOV.UK. Weighing and measuring equipment used in business must be passed as fit for use for trade by a Weights and Measures Inspector or an approved verifier.

A scale that is repaired or adjusted has to be passed again, by the Inspector or an approved verifier. OPSS describes an approved verifier as a manufacturer, installer or repairer allowed to pass certain types of equipment.

Packing goods to sell

GOV.UK's guide to packaged goods says the equipment has to be suitable. It goes on to say that you cannot use domestic scales to weigh goods you intend to sell.

The same guide says Your local Trading Standards office will tell you what is suitable equipment for your business sector.

Grams and kilograms

GOV.UK says sellers must use metric measurements (grams, kilograms, millilitres or litres) when selling packaged or loose goods in England, Scotland or Wales. Northern Ireland has different rules.

A seller can show an imperial weight alongside the metric one. GOV.UK says it cannot stand out more than the metric measurement.

GOV.UK names three things that can still be sold in imperial measures. They are draught beer or cider by the pint, milk in returnable containers by the pint, and precious metals by the troy ounce.

The rules for the scales themselves

The Non-automatic Weighing Instruments Regulations 2016 cover scales that need a person to operate them, such as a shop's counter scale. OPSS publishes guidance on them, with one version for Great Britain and one for Northern Ireland. It sets out the duties of manufacturers, importers and distributors, among others.

Local Trading Standards enforce most UK weights and measures law, OPSS says. In Northern Ireland that falls to the Department for the Economy.

Weighing at home

Stand the scale on a firm, flat surface. Set it to zero before anything goes on, and again after you put a bowl on it.

Useful links