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Weighing and measuring fish

14 June 2024


Requirements when selling fish loose and/or prepacked

This guidance is for England, Scotland and Wales

There are a number of legal requirements that you need to be aware of when selling fish by weight (whether at the request of customers or prepacked ready for sale), which include weighing equipment construction and quantity price marking. Examples of these requirements include using a 'Government stamped' scale (as they are known), pricing and selling in metric quantities and marking prepacked goods with the weight of the product.

Customers must be informed of the weight before paying for and receiving their goods. In general all foods, whether sold loose from bulk or prepacked, must be priced in a manner that can be seen by customers without them having to ask.


Weights and measures legislation applies to the sale of fish that is fresh, chilled, frozen, salted, cooked or processed. It also covers products that are made substantially of fish, but does not apply to fish paste.

In general, fish and fish products must be sold by the kilogram.

Prepacked items must be marked with the net weight of the product in metric units. This is not required on packs of fish pies, puddings or flans where the pack is marked with the number of items or where the number of items can be seen without opening the pack. Very small packs containing less than 5 g of product do not require the net weight to be marked on them.

Loose or non-prepacked items, including products cut or selected from a larger bulk as requested by the customer, must be sold either by net weight or by gross weight. Products can be sold by gross weight if the weight of the bag, wrapper or container in which the product is served is not greater than that allowed for in the table below.

These requirements do not apply to:

  • fish pies, puddings or flans
  • sales of less than 5 g of product
  • jellied, pickled or fried fish
  • fish sold otherwise than from a market, shop, stall or vehicle (directly from a boat, for example)

Your local Trading Standards service will be able to give you more detailed advice regarding which products the above exemptions apply to.


  • net weight means the weight of the goods alone without the bag, wrapper or container
  • gross weight means the weight of the goods plus the weight of any bag, wrapper or container
  • tare weight means the weight of any bag, wrapper or container
Weights for fish sold gross in a container
Gross weightPermitted weight of container
Up to 500 g5 g
More than 500 gA weight at the rate of 10 g per kg of the gross weight


Scales that are used must be accurate and of an approved construction for retail sale use, and have certain required markings and stamps on them. See 'Weighing equipment for legal use' for more information.

The customer must be informed of the weight of the product and the price before paying for it. This can be done by:

  • weighing the product in front of the customer so that they have a clear view of the weight indication on the scales
  • marking the weight on the bag, wrapper or container
  • marking the weight on a separate ticket or till receipt

In the case of customer requests for fish that has been boned, trimmed, cleaned, etc the customer should be advised whether the weight to be charged for will be before or after the product is prepared for them.


There are no specific legal requirements regarding the sale of shellfish, which can therefore be sold by weight, volume or by the traditional shellfish-stall tub, pot, saucer, etc. Any weight or volume used to sell shellfish by must be a metric quantity - grams, kilograms or litres - and 'Government stamped' weighing and measuring equipment should be used to determine the quantity sold. If shellfish is sold without reference to a quantity, the price for each tub, pot or saucer should be clearly indicated to customers.


This guide is intended for traditional businesses supplying products at the request of customers.

If your business also prepares large quantities of prepacked products in set quantities - for example, 500 g packs of frozen fish - you may wish to take advantage of packing them using the average-quantity system, which makes allowances for small variations in package weights.

For more information on this system please see 'Packaged goods: average quantity'. You may also wish to seek specific advice from your local Trading Standards service.

If you also make pre-prepared foods, such as ready meals, that require heating or cooking and are sold direct from your premises, then these should be marked with a net weight declaration. The net weight declaration is the total net weight of any individual components, excluding any packaging materials (tare weight) and can also be packed using the average-quantity system.


In general, all foods must have their price displayed and include VAT where applicable.

The price must be displayed on or near the product, be unambiguous and easily read by customers without them having to ask for assistance.

For most non-prepacked items or for products where the customer requests a particular quantity, the unit price per kilogram must be indicated on or near the goods, or on a price list. An exemption from this is cooked or ready-to-eat fish, which should be priced per 100 g. You may also display a price per pound, but this must not be more prominent than the metric kilogram price. For more expensive products you may also assist customers with an additional price per 100 g where this might give a more meaningful indication of the price the customer will have to pay.

For fish counters in shops with a sales area of more than 280 m2, the unit price of prepacked products must also be displayed on or near the goods - for example, on a shelf edge ticket or a price list.

However, there are exceptions; the main ones are as follows:

  • products near their expiry date and sold at a reduced price
  • products that are not required to be sold by weight - for example, fish pies, puddings and flans
  • an assortment of different items sold as a single pack - for example, 'Cod and chips'
  • any product where the unit price is identical to the selling price

The unit price must be in metric, generally the price per kilogram. The unit price per pound may also be given in addition to the metric marking, but must be given less prominence.

For more information on pricing generally, see 'Providing price information'.


There are a number of food labelling requirements that you will also need to comply with when selling these products. For more information see the guidance in this website's 'Food' section.


For more information on the work of Trading Standards services - and the possible consequences of not abiding by the law - please see 'Trading Standards: powers, enforcement and penalties'.


No major changes.

Last reviewed / updated: November 2023

Key legislation

Please note

This information is intended for guidance; only the courts can give an authoritative interpretation of the law.

The guide's 'Key legislation' links may only show the original version of the legislation, although some amending legislation is linked to separately where it is directly related to the content of a guide. Information on changes to legislation can be found on each link's 'More Resources' tab.

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