Food (Standards & Composition)

Weights and measures for fishmongers

In the guide

This guidance is for England, Scotland & Wales

There are a number of legal requirements that fishmongers need to be aware of when selling products by weight (whether at the request of customers or prepacked ready for sale), which include weighing equipment construction and quantity price marking. For example, 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 & measures requirements

In relation to the fishmonger trade, 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 the number of items can be seen without opening the pack. Very small packs containing less than 5g of product do not have to have the net weight marked on them.

Non-prepacked items, including products cut or selected from a larger bulk as requested by the customer, must be sold by net weight or 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 5g 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

Table of container weights

Weights for fish sold gross in a container:

Gross weight Permitted weight of container
up to 500g 5g
more than 500g a weight at the rate of 10g 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 he has 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 boned, trimmed or cleaned fish etc the customer should be advised whether the weight to be charged for will be before or after the product is prepared for him.


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.

Average quantity

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

If your business also prepares large quantities of prepacked products in set quantities - for example, 500g 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.

Price marking requirements

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 100g. 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 100g where this might give a more meaningful indication of the price the customer will have to pay.

For fishmonger counters in shops with a sales area of more than 280 square metres 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.


Failure to comply with the above requirements is a criminal offence.

The maximum penalty for breaching the weights and measures requirements is a fine.

The maximum penalty for breaching the price marking requirements is a fine and two years' imprisonment.

Key legislation

Last reviewed / updated: September 2017

PixelPlease 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 amendments to UK legislation can be found on each link's 'More Resources' tab; amendments to EU legislation are usually incorporated into the text.

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