Guide summary

Have your equipment requalified by an inspector or approved verifier after any repair or adjustment
Do not use domestic scales to make up packaged goods
Look for the marks or stamps that show your equipment has been passed for trade use
Choose the minimum system (every package holds at least the stated quantity) or the average system
Keep average system sample records for at least 1 year from shipping, or until the use-by date if shorter
You can show an imperial measurement beside the metric one, but it must not stand out more
Sell draught beer and cider in a third, half or two-thirds of a pint, or multiples of half a pint
Using equipment not passed for trade is an offence, and the equipment can be forfeited

Your local Trading Standards service enforces the weights and measures rules and can tell you what equipment and checks suit your business.

Weights and Measures Act 1985

Requires retailers selling goods by weight, measure or number to use equipment passed as fit for use for trade, and packers to meet the packaged goods rules. Protects consumers from short measure and ensures fair trading.

When you need equipment passed for trade

If you sell goods by weight or measure in any of these situations, your equipment must be passed as fit for use for trade:

Selling loose goods by weight, such as fruit, vegetables, cheese or deli counter goods
Making up orders by weight
Selling fuel by volume, such as petrol or diesel

If you make up packaged goods, the equipment must be suitable for the job. You cannot use domestic scales. Your local Trading Standards office can tell you what is suitable.

Equipment for trade use

Weighing and measuring equipment used for trade must:

Be passed as fit for use for trade by a Weights and Measures Inspector or an approved verifier
Carry the marks or stamps that show it has been passed
Be requalified by an inspector or approved verifier after any repair or adjustment

There is no set interval for re-testing equipment that has not been repaired or adjusted.

Packaged goods

Packaged goods must:

State the weight or volume on the label
Use metric units (grams, kilograms, millilitres or litres)
Be packed under the minimum system (every package holds at least the stated quantity) or the average system

The average system

If you pack to the average system, you must meet the three packers' rules:

The contents must not be less, on average, than the quantity on the label
Only a small number of packages may fall short by more than the tolerable negative error, few enough for the batch to pass the reference test
No package may be short by more than twice the tolerable negative error

You must keep records of your sample checks for at least one year from the date you ship the packages, or until the use-by date if that is shorter. Packages of up to 10 kg or 10 litres packed this way may carry the ℮ mark, but the mark is optional.

Metric and imperial measures

You must use metric measurements. You can show an imperial measurement alongside, but it must not stand out more than the metric one.

Exceptions: draught beer and cider by the pint, milk in returnable containers by the pint, and precious metals by the troy ounce. Draught beer and cider must be sold in a third, half or two-thirds of a pint, or multiples of half a pint.

Penalties

Using equipment that has not been passed for trade is an offence, and the equipment can be forfeited.
If you break the packaged goods rules, you can be fined or sent to prison.

Equipment purchase: Equipment suitable for trade use
Before first use: Passed as fit for use for trade
After repair or adjustment: Requalified by an inspector or approved verifier
Average system records: Results of sample checks, kept for 1 year or until the use-by date if sooner
Staff training: Correct use of scales and basic checks
Pre-packing quality control: Sample checks against the three packers' rules
Metric display: Metric first; imperial no more prominent

Weights and measures guidance (opens in a new tab)

Sell some goods in fixed sizes

Some goods must be sold in fixed sizes, known as specified quantities. For example, gin, rum, vodka and whisky sold by the glass must be in 25ml or 35ml measures and their multiples, but not both on the same premises.

Pack and label packaged goods

Packaged goods are sealed products of between 5g and 25kg, or 5ml and 25 litres, made up in the same quantity as others of their type.

Keep your average system records for at least one year from the date you ship the packages or the use-by date, whichever is shorter.

The quantity on the label must be permanent, easy to see and at least the minimum height. If you produce or import packaged goods, you are responsible for packing and labelling them correctly, and you can be fined or sent to prison for breaking the rules.

Metric pricing and labels

Show quantities in metric units, with any imperial figure no more prominent.
Trade-approved equipment

Buy weighing and measuring equipment passed as fit for use for trade, and have it requalified by an inspector or approved verifier after any repair or adjustment.
A packing method

Choose the minimum or the average system for each packaged product. Ask Trading Standards for help with the average system.
Sample records

If you use the average system, record each sample batch and keep the records for at least a year.

Legal basis

Primary legislation and key regulations

Weights and Measures Act 1985 Primary 1985 · UK-wide Weights and Measures (Packaged Goods) Regulations 2006 SI 2006 · UK-wide

Browse UK legislation legislation.gov.uk

Official guidance

Weights and measures for businesses (opens in a new tab)

GOV.UK · Great Britain

Weights and measures: business guidance (opens in a new tab)

OPSS

Sell goods by weight or measure

Sell some goods in fixed sizes

Pack and label packaged goods

Metric pricing and labels

Trade-approved equipment

A packing method

Sample records

Legal basis

Official guidance

Related guides in Consumer Rights

Sell safe products with the right conformity marking

Measure, pack and label goods you sell by weight or volume

Sell eggs, honey and produce from home or the farm gate