What Is an Import Duty Rate?
An import duty rate is a percentage applied to the value of imported goods to determine how much tax you owe at the border. These rates are set by the importing country's government and vary by product type, country of origin, and any applicable trade agreements in force.
Duty rates exist to generate government revenue, protect domestic industries from cheaper foreign competition, and — in some cases — to discourage the import of certain goods for health or environmental reasons.
What Is "Customs Value"?
Before you can calculate duty, you need to know the customs value of your goods. This is not simply what you paid on a website. The most widely used method — set out by the World Trade Organization (WTO) — is the transaction value method, which is broadly:
Customs Value = Cost of Goods + Cost of Insurance + Freight to the Port of Entry (CIF)
Some countries (notably the USA) use FOB (Free on Board) value instead, which excludes international freight and insurance from the dutiable value. Always check the rules for the specific country you're importing into.
How Import Duty Is Calculated
Once you have the customs value, the calculation is straightforward:
- Find the HS code for your product (the international product classification number)
- Look up the duty rate that applies to that HS code in the destination country
- Multiply: Customs Value × Duty Rate = Import Duty Owed
For example, if you import clothing worth £500 (including shipping and insurance) into a country with a 12% duty rate on apparel, you would owe £60 in import duty.
Types of Duty Rates
| Type | How It Works | Example |
|---|---|---|
| Ad Valorem | A percentage of the customs value | 10% of £200 = £20 duty |
| Specific Duty | A fixed amount per unit, weight, or volume | £1.50 per kg |
| Compound Duty | A combination of ad valorem and specific | 5% + £0.50 per unit |
| Anti-Dumping Duty | Extra duty to counteract underpriced imports | Varies by product and country |
VAT on Top of Duty
In most countries, VAT (or GST) is charged on top of the customs value plus any import duty. This means VAT is calculated on a higher base than just the goods' price. For example:
- Customs value: £500
- Import duty (10%): £50
- VAT base: £550
- VAT (20%): £110
- Total charges: £160
How Trade Agreements Affect Duty Rates
The rates above assume Most Favoured Nation (MFN) status — the standard rate applied to countries without a special trade agreement. If the exporting country has a Free Trade Agreement (FTA) with the importing country, duty rates may be significantly reduced or even zero, provided you can prove the goods' origin with the correct documentation (such as a certificate of origin or a supplier's declaration).
Where to Find Duty Rates
- UK: The UK Global Tariff (Trade Tariff tool on gov.uk)
- EU: European Commission's TARIC database
- USA: USITC Harmonized Tariff Schedule
- Australia: ABF Tariff Working Pages
These are all free, publicly accessible tools where you can enter an HS code and find the applicable duty rate for your destination country.
Summary
Import duty is calculated as a percentage of the customs value of your goods, using a rate determined by the product's HS code. Remember to account for VAT on top, and always check whether a trade agreement could reduce your rate. Getting these numbers right before you import helps you budget accurately and avoid unpleasant surprises at the border.