Trading Standards

Weights and Measures

Your questions answered

This authority will react to complaints received on short measures, visit trading premises to check weighing and measuring equipment used for trade as well as verifying that measuring equipment are accurate.

Quantity or weight?

Many categories of goods are required by law to be sold with reference to quantity. Most food items including meat, fish, cheese and fruit and vegetables generally need to be sold by weight.

Loose or pre packed?

Products like the fuel we put in our cars and oil for our central heating systems are sold by volume. For transactions in goods such as carpets and timber it is the measurement of area or length that is important.

Weights and measures law makes a distinction between goods sold loose from bulk and those which are pre-packed. Loose from bulk sales take place when the quantity required by the customer is determined at the time of purchase.

In these circumstances any equipment needed to measure the quantity is operated during the transaction. When selling loose from bulk the trader must give an indication of the unit price e.g. The price per litre of petrol.

Whatever quantity the customer requires he can work out the price to pay from this price indication. The alternative to this is pre-packing where the goods are packed ready for sale before the customer arrives.

This can equally include a punnet of strawberries made up by your greengrocer or a packet of crisps packed in a factory many miles away. The requirement here is that packs are marked with an accurate indication of quantity.

What is the average quantity system?

Goods which are pre-packed away from the premise they are sold at are generally subject to a set of rules known as the average quantity system.

The system operates throughout Europe and is denoted by the 'e' mark. It allows some packs to be slightly under the quantity stated provided the overall average of any batch does not drop below this.

It is not truly an average quantity system as a strict set of rules operate to control the proportion of under weight packs and to limit the extent to which an individual pack can be deficient.

Trading Standards Officers carry out tests at the production level to ensure that packers are complying with average quantity legislation.

What do I do if I'm sold short weights or measures?

The Weights and Measures Act makes it an offence to sell short weight or measure. This applies equally to loose sales and pre-packs and regardless of whether the sale was by weight, measure or length.

The Trading Standards service can take action against traders who flout the rules and you should contact your local department if you believe you are not getting what you pay for.

Why must equipment used for trade comply with the law?

All weighing and measuring equipment used for trade must comply with weights and measures law. This can be anything from a beer glass to a road tanker.

Whether it is equipment which you operate yourself such as a petrol pump or something normally operated by the trader like a shop scale, any equipment used to establish a sale by quantity will be subject to initial approval and regular inspection by the Trading Standards service.

This ensures accuracy and protects against fraud.

Why metrication?

Although something of a political hot potato the UK has gradually adopted the metric system of weights and measures.

Imperial units such as pounds, ounces, yards and gallons have largely been phased out and replaced by the kilogram, metre and litre. In some circumstances such as milk from the milk man and beer sold in the pub imperial units like the pint remain in use.

There are also circumstances where imperial measures can be provided as supplementary indications to ease the transition to the metric system.

Why is there a hierarchy of standards?

The cornerstone of the weights and measures system is of course the consistency of the units used. A kilogram must always be a kilogram regardless of where you shop.

Trading Standards Departments maintain highly accurate standards of the various units of measurement, these are traceable to standards held at a national and even international level.

Similarly the weights used to test scales in the high street are themselves checked with reference to laboratory kept standards.

Points to remember on weights and measures

This service provides free advice on weights and measure law.

1. All spirit measuring instruments use for selling gin, whisky, rum or vodka must:

Have been stamped
Placed where customers can see when in use
Marked with the notice or certificate number

2. Did you know that spirit measuring and capacity measures must be stamped?

Public houses are required to stamp their measures used to sell spirit such as gin, whisky, vodka and rum
Pubs are required to serve beer in stamped pint or half-pint glasses
It is an offence to serve short measure

3. Did you know that all loose fruit and vegetables must be sold by weight?

Loose fruit or vegetable can be sold by either net or gross weight i.e. Without wrapping or with the wrapping material
Fruit and vegetables must be packed in metric quantities
All bags of pre packed produce must indicate a marked weight or number

4. Did you know that bread loaves must have certain weights?

Bread loaves must weigh 400g, 800g, or 1200g which are known as prescribed weights. Most of the bakers use an average weight in baking different type of loaf

Did you know?

All spirit measuring instruments used for selling gin, whisky, rum or vodka must have been stamped; placed where customers can see they are in use; marked with the notice of certificate number and use dispense quantities of either 25ml or 35ml
Beer and wine glasses must be stamped
It is an offence to serve a short measure
Most loose fruit and vegetables must be sold by weight. They can be sold by either net or gross weight
Fruit and vegetables must be packed in metric quantities
All bags of pre-packed produce must indicate a marked weight or number
Bread loaves must weigh either 400g, 800g or 1200g. This is known as a prescribed weight. Most bakers use an average weight in baking different type of loaves

For advice on all matters concerning weights and measures legislation and testing of equipment, please contact Trading Standards.