The big pack looks cheaper. Sometimes it is. A unit price answers the question in one number.

GOV.UK guidance (published 22 September 2025) on the Price Marking Order 2004 covers goods sold by traders to consumers, including online. It applies to Great Britain; Northern Ireland has its own order. The guidance describes the Order as amended, with the amendments taking effect on 6 April 2026.

Two prices

  • Selling price: the total price you pay for the quantity bought, including VAT and other taxes. A deposit is shown separately.
  • Unit price: the price per item for goods sold by number, otherwise per kg, litre, metre, square metre or cubic metre. If a product can be sold by weight or volume and is labelled with only one, the unit price must be per kg or per litre.

The guidance's worked examples: cereal at £3 for 500 g is £6 per kg; £3 for 2 kg is £1.50 per kg; ketchup at £1 for 500 g is £2 per kg; 4 apples at £3 is 75p each.

Who is exempt

A "small shop" is one with a relevant floor area of 280 square metres or less. The guidance's examples: a shop of 250 square metres must show the selling price; one of 290 square metres must show both prices. In a small shop the unit price is not required for pre-packaged products in a constant quantity, but this does not apply to products sold from bulk. Other unit price exemptions in the guidance include products reduced because of damage or because they are about to spoil, certain assortments of different items sold as a package or as a multi-item offer, and products whose unit price is identical to their selling price.

Online and promotions

Adverts that invite you to conclude a distance contract, such as goods sold direct from the internet, must show selling and unit prices; catalogues must show both as relevant. For a multi-buy on identical items, such as the guidance's "2 for £3" crisps example, the offer's selling and unit price must be shown in addition to the regular ones.

Per-100 ml figures for beauty products are our own comparison method, not a legal unit. We cannot say how a particular online shop applies these rules; the guidance is general and not legal advice.

Last checked: 21 October 2026. General information, not legal, medical or financial advice. Sources: GOV.UK, Price Marking Order 2004: government guidance (published 22 September 2025; accessed 15 October 2026).