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Commodity Codes

Every item that crosses an international border needs a commodity code — a numerical classification that tells customs authorities exactly what the goods are. The code determines the duty rate, so an incorrect one means paying the wrong duty, and can also trigger a customs examination or a penalty from HMRC.

This guide explains what commodity codes are, how to find the correct one, and what the consequences of getting it wrong can be.

What Is a Commodity Code?

A commodity code is a numerical identifier assigned to a specific type of goods. It is used by customs authorities worldwide to classify goods consistently, which in turn determines the duty rate, any import controls, and eligibility for preferential tariff rates under trade agreements.

In the UK, commodity codes are 10 digits for imports and 8 digits for exports. The first six digits are based on the internationally standardised Harmonised System (HS), developed by the World Customs Organisation and used by over 200 countries. The remaining digits are added by individual countries to provide more granular classification for their own tariff purposes.

This means the first six digits of a UK commodity code will match those of the equivalent code in, say, Japan or the EU — which matters when claiming preferential rates under a trade agreement.

How the Harmonised System Is Structured

The HS is organised into 21 sections and 97 chapters, covering everything from live animals (Chapter 1) to works of art (Chapter 97). Within each chapter, goods are divided into headings (four digits) and subheadings (six digits), becoming progressively more specific.

For example: Chapter 61 covers knitted or crocheted clothing. Heading 6109 covers T-shirts and similar garments. Subheading 610910 covers those made of cotton. The UK then adds a further four digits to make finer distinctions within a subheading — under 610910, the full 10-digit codes separate T-shirts (6109100010) from the other garments in the subheading (6109100090).

Classification follows the HS General Rules of Interpretation — a set of legal rules that determine which heading applies when goods could arguably fall into more than one category. This is where professional classification advice becomes valuable for complex products.

Using the UK Trade Tariff to Find Your Code

HMRC provides a free online tool — the UK Trade Tariff — at trade-tariff.service.gov.uk. You can search by product description or browse the chapter structure. The tool shows the applicable duty rate, VAT treatment, any trade remedies or anti-dumping measures, and the applicable preference rates under UK trade agreements.

When searching, use specific, technical language rather than brand names or colloquial terms. "Cotton woven fabric, plain weave, 200g/m²" will return better results than "cotton material". If you're unsure where a product sits, browse the chapter that seems most relevant and read the chapter notes — these are legally binding and often clarify ambiguous cases.

If you're still unsure, HMRC's Tariff Classification Service will give you informal advice on the correct code by email — helpful, but not legally binding. For legal certainty, apply for an Advance Tariff Ruling (ATR) through HMRC's separate ruling service before you import: the ruling is binding on HMRC, and decisions typically take between 30 and 120 days.

Consequences of Using the Wrong Code

An incorrect commodity code is not just an administrative error — it has direct financial and legal consequences.

Wrong duty rate: If the correct code carries a higher duty rate than the one you used, HMRC can recover the underpaid duty, plus interest. If the correct code carries a lower rate, you've overpaid — but HMRC won't proactively refund you unless you claim it.

Penalties: HMRC can issue a civil penalty for an inaccurate customs declaration under the Customs (Contravention of a Relevant Rule) Regulations 2003. These are fixed amounts of up to £2,500 per contravention — in practice they typically start at £250 and escalate through £500 and £1,000 for repeated errors — and carry no implication of dishonesty. HMRC also recovers any underpaid duty, plus interest.

Shipment delays: An incorrect code may trigger a customs examination or hold, delaying delivery to your customer. For time-sensitive goods this can be extremely disruptive.

Import controls: Some commodity codes require licences, certificates, or advance notifications. Using the wrong code might mean you've inadvertently bypassed a control — and customs will find out when they check the actual goods.

Tips for Complex or Unusual Products

Multi-component products can be difficult to classify. A machine that performs multiple functions is generally classified by its primary function; if no single function predominates, different rules apply. Mixtures and sets have their own classification rules. Products that are "new to market" — such as novel materials or tech products — may require professional classification because existing codes don't fit neatly.

If your goods are genuinely complex, the cost of getting professional classification advice from a customs broker or trade consultant is almost always less than the cost of getting it wrong.

Commodity Codes and ClearDuty

ClearDuty uses your commodity code as the primary input for calculating import duty. If you're unsure of your code, you can look it up using the UK Trade Tariff tool before running your calculation. Getting the code right at the research stage means your duty estimate will be accurate — and you won't face any surprises when your goods arrive.