Commodity codes are internationally recognised reference numbers. A code describes a specific product when importing or exporting goods. You will use this code on any customs declarations and can find them in the Trade Tariff tool. Although many countries have signed up to the same classification system, only the first 6 digits are used worldwide and product specific decisions are particular to each country. If you rely on the commodity code from an overseas supplier, you’ll need to check if the treatment is the same and how much of the code applies in the UK. It’s important to understand that it is the importer or exporters responsibility to declare the correct commodity code and give a clear instruction to the customs clearance agent. 

You’ll need to find the right commodity code for any goods you import or export, as it works out: the rate of Customs Duty and import VAT taxes preferential rates which may apply

The Trade Tariff tool will also help you check if:

you need a licence to move your goods
you could pay less Customs Duty (for example because your goods are covered by a trade agreement)
your goods are covered by:
agricultural policy
anti-dumping duties
UK safeguarding measures
tariff quotas