Weights and measures law in Great Britain is primarily designed to ensure fair trading, meaning consumers receive accurate quantity and price information when buying goods by weight.
1. Core Legal Framework
Primary Legislation
- The Weights and Measures Act 1985 is the main statute governing trade measurements in Great Britain. It sets out the legal units of measure and provides the basis for detailed regulations and enforcement.
Secondary Regulations
- The Non-Automatic Weighing Instruments Regulations 2016 cover technical requirements and market conformity for scales used in trade (including UKCA/CE marking and conformity assessment before placing on the GB market).
- The Weights and Measures (Packaged Goods) Regulations 2006 govern the quantity marking and tolerances for pre-packed goods.
- The Price Marking Order 2004 (and amendments) establishes requirements for selling and unit price display in retail.
2. Trade Approved Scales and Equipment Requirements
Use of Approved Scales (Legal-for-Trade)
- Trade-approved (legal-for-trade) weighing scales must be used when you sell items where the price is dependent on weight. Domestic or unapproved scales cannot lawfully be used for transactions.
- Scales must be accurate and suitable for the goods and quantities being weighed. Trading Standards will inspect equipment to ensure it is appropriate and accurate.
- Weighing equipment must be verified and stamped as fit for trade, either by a Weights and Measures Inspector or an approved verifier/manufacturer.
- If scales are adjusted or repaired, they usually must be re-verified before further use in trade.
- Scales used must be compliant with the Non-Automatic Weighing Instruments Regulations 2016 and marked accordingly (UKCA/CE and M marking where required).
Failing to use approved scales where required can lead to prosecution and significant fines.
3. Consumer Information at Point of Sale
Visible Weight Display
When selling products weighing them at the request of the consumer (for example at a deli, butcher, fruit & veg stall), the customer must be informed of the weight of the product before payment. This can be done by:
- showing the weight on scales in view of the customer,
- marking the weight on the bag/container,
- or printing the weight on the receipt or a separate ticket.
This requirement applies generally to non-prepacked goods sold by weight (e.g., loose fruit, vegetables, cheese).
Unit Pricing (Price per Kilogram)
- Under the Price Marking Order, where goods are offered for retail sale (especially loose items), the selling price and the unit price per kilogram (or litre where relevant) must be clearly displayed to the consumer.
- This display should be legible, unambiguous, and include VAT where applicable.
- For products sold by weight, the unit price per kg must be shown; additional unit prices per 100g may be given where helpful, but metric display must be primary.
Although there is no express statutory requirement that the receipt itself must contain the weight, the law requires that customers must know the weight before sale and that pricing information (incl. weight/quantity and unit price) be clearly available. Issuing a receipt with the weight and price breakdown is a standard and effective way to meet this obligation.
4. Pre-Packed Goods
Label Weight Requirements
- For pre-packed goods (sealed before sale), the weight or volume must be shown on the label with clear and legible markings.
- Quantity marking must meet the regulatory minimum height and visibility requirements.
- You must use metric units as the primary measurement, though imperial may be shown in addition.
5. Units and Metrication
Metric Units Required
- Items sold by weight must generally be sold and displayed using metric units (grams and kilograms). Imperial units (e.g., pounds) can be shown only as a supplementary indicator and must not be more prominent.
This reflects long-standing UK metrication requirements in weights and measures law.
6. Enforcement and Penalties
- Local Trading Standards officers enforce these legal requirements, including scale verification, price and unit price display, and accurate quantity information.
- Failing to comply with weights and measures or unit pricing rules can lead to prosecution, fines, and other enforcement actions.
Disclaimer. This summary is provided for general guidance only and should not be treated as legal advice. Retailers should confirm their specific obligations with Trading Standards or a qualified compliance adviser.
