Everything you need to install, configure, and maximise Tax & Duty King for your international customers.
Follow these five steps to go from installation to live import fee calculations in under 15 minutes.
Visit the Tax & Duty King listing and click Install. Approve the requested permissions — these allow the app to read your products for HS classification and write HS codes back to Shopify inventory items.
Open the Settings tab. Set your Store Country of Origin — the country your goods are manufactured in or shipped from. This determines whether TCA, IOSS, or other trade agreements apply to your shipments.
Go to the HS Codes tab. Click Classify All with AI to run the AI classification engine. Review suggestions, approve correct ones, override any that need adjustment, then click Push All to Shopify to sync the codes.
In Shopify Admin, go to Online Store → Themes → Customize. Navigate to your cart template. In the left panel, find the Apps section and add the Tax & Duty King block. Drag it to your preferred position and save.
Use a VPN set to a supported country (e.g. Germany or the USA) and add a product to your cart. You should see the import fee breakdown appear. If the widget isn't showing, see our Troubleshooting Guide.
An HS code (Harmonized System code) is a 6-digit number used by customs authorities in every country to identify a product and determine the applicable import duty rate. The system is maintained by the World Customs Organization and used by 200+ countries.
For example, 9004.10 is the HS code for sunglasses. A pair of sunglasses shipped from Germany to the UK would attract a 2.7% UK import duty based on this code (unless TCA zero-duty applies).
An HS code is hierarchical. The first two digits are the chapter, the first four are the heading, and all six form the subheading used for duty determination.
| Level | Digits | Example | Meaning |
|---|---|---|---|
| Chapter | First 2 | 90 | Optical & photographic instruments |
| Heading | First 4 | 9004 | Spectacles, goggles and the like |
| Subheading | All 6 | 9004.10 | Sunglasses |
How zero-duty rules work for EU-origin goods arriving in the UK.
The UK–EU Trade and Cooperation Agreement (TCA), which came into force on 1 January 2021, allows goods with proven EU origin to be imported into the UK with zero customs duty. Without TCA, most goods would attract UK Global Tariff rates of 6–12%.
When a customer's delivery address is in the United Kingdom and your store's country of origin is set to an EU member state, Tax & Duty King applies TCA zero-duty logic automatically. The widget shows 0% customs duty for eligible products.
TCA zero-duty only applies if the goods genuinely originate in the EU. The key criteria:
The Import One Stop Shop (IOSS) is an EU VAT scheme for UK sellers shipping goods to EU customers. It applies to shipments valued at €150 or less. Under IOSS, the UK seller registers for EU VAT and collects it at the point of sale — EU customers receive their parcels without unexpected courier VAT bills at the door.
Note: IOSS covers VAT on UK→EU shipments. It is separate from the UK–EU TCA, which covers import duty on EU→UK shipments. Both may apply to the same product depending on the trade route.
Tax & Duty King handles IOSS by displaying the VAT-inclusive price in the cart widget for eligible shipments: UK seller shipping to an EU destination, order value under €150, and IOSS registration active in Settings. The widget shows the VAT amount as "collected at checkout" rather than as a separate import fee, preventing surprise charges at delivery.
The value below which imported goods are exempt from customs duty. Tax & Duty King applies these automatically.
| Country | Duty-Free Threshold | VAT-Free Threshold | Notes |
|---|---|---|---|
| 🇬🇧 United Kingdom | £135 | £0 (VAT always applies) | IOSS applies for UK sellers |
| 🇪🇺 EU Member States | €150 | €0 (VAT always applies) | IOSS applies for registered sellers |
| 🇺🇸 United States | Subject to change | N/A | AI agent monitors for updates |
| 🇨🇦 Canada | C$20 | C$20 | GST/HST applies above threshold |
| 🇦🇺 Australia | A$1,000 | A$0 (GST always applies) | GST collected at checkout |
| 🇨🇭 Switzerland | CHF 5 | CHF 65 | Swiss VAT rate: 8.1% |
The Tax & Duty King widget is added via the Shopify Theme Editor. It can be placed in the cart drawer, cart page, and product page.
In Shopify Admin, go to Online Store → Themes. Click Customize on your active theme.
Use the page selector at the top of the editor to navigate to Cart. For the product page widget, navigate to Products → Default product.
In the left sidebar, click Add block. Scroll to the Apps section and select Tax & Duty King. Drag it to your preferred position.
Click Save. Test by using a VPN set to a supported country and adding a product to your cart. The import fee widget should appear.
Widget not showing? See the full troubleshooting guide →
Three autonomous agents keep your rate data accurate without any manual work.
Monitors EU VAT rates via euvatrates.com and non-EU rates via GPT-4.1 AI research. Automatically updates the VAT rate database when changes are detected. Full change history with source citations available in the VAT Rates tab.
Monitors WTO tariff schedules and trade agreement updates. Detects changes to duty rates for your specific HS codes and alerts you via the dashboard. Handles TCA, de minimis threshold changes, and trade policy updates.
Fetches live exchange rates for all 166 supported currencies daily. Import fees are always displayed in the customer's local currency using the most current rate. Full rate history available in the Currency Rates tab.