· ReadyStack
Worked example
Real numbers from this tool, line by line.
A UK online seller who is not VAT-registered and imports 200 cotton T-shirts at £3.00 each pays £4.89 a unit once they land, not £3.00.
| Line | Amount |
|---|---|
| Goods (200 T-shirts) + £120 shipping = customs value | £720.00 |
| Customs duty, 12% of £720.00 | £86.40 |
| Import VAT, 20% of £806.40 | £161.28 |
| DHL Express fee for paying it | £11.00 |
| To pay before delivery | £258.68 |
| Landed cost | £978.68 |
| Landed cost per unit | £4.89 |
That is 63.00% above the supplier price. If you price your listings from the £3.00 on the Alibaba invoice, every sale starts £1.89 short.
How each line is worked out
Customs duty is charged on the price you paid plus postage, packaging and insurance. The rate comes from the commodity code on the UK Trade Tariff: cotton T-shirts (6109100010) from China pay 12%. Look your own code up on trade-tariff.service.gov.uk.
Import VAT is charged on the total package value: the goods, the shipping and the duty. So the duty is taxed again: 20% of £806.40 is £161.28.
The carrier then charges you for paying both at the border. DHL Express UK charges £11.00 or 2.5% of the duty and VAT it pays, whichever is greater. On £247.68 that is £11.00; it only rises above £11.00 when duty and VAT pass £440. FedEx, UPS and Royal Mail set their own fees, so type yours into the calculator.
The line most duty calculators leave out: is the VAT yours to keep?
If your turnover is under the £90,000 VAT registration threshold, you cannot reclaim import VAT. The £161.28 stays in your cost, and that is why the T-shirts land at £4.89.
A VAT-registered seller can use postponed VAT accounting. The import VAT goes on the VAT Return instead of being paid at the border, and is recovered under the normal rules. The same order then needs £97.40 before delivery, lands at £817.40 and costs £4.09 a unit. Registering also means charging VAT on your sales, so ask your accountant before you register just for this.
Orders of £135 or less
HMRC charges no Customs Duty on non-excise goods worth £135 or less. The £135 is the value of the goods without shipping. VAT is still due: the overseas seller charges it at checkout instead of the carrier collecting it.
Example: 40 toy sets for £120 plus £25 shipping pay no duty and £29.00 VAT at checkout. Landed cost: £174.00, or £4.35 a set against £3.00 from the supplier.
What changes next
HMRC published draft legislation on 13 July 2026 that removes the £135 relief. It comes into force on a date the Treasury sets, by October 2028 at the latest. After that, the same toy order pays duty too: 4% of £145.00 is £5.80. The calculator's last line shows that amount for your own order, so you can see what the change costs you before it lands.
Why a free duty calculator is not enough
Free calculators price the duty and VAT for one shipment. SimplyDuty gives 5 free calculations a day, then charges £9.99 to £99.99 a month. They leave out the carrier fee and whether the VAT is a cost you keep, so they cannot give a landed price per unit.
Check your own order
Type your goods value, units, shipping, duty rate, VAT status and carrier fee terms; the free calculator shows every line above for your order.
The $21 workbook keeps it: a 25-shipment log for every order this year, the same order VAT-registered and not registered side by side, and the HMRC rules with their sources, checked 25 October 2026.
A calculation aid, not customs or tax advice.
15 seconds — what it actually does
Questions people ask
What does this import duty calculator work out?
It works out what one stock order from outside the UK really costs you once it lands: customs duty on goods plus shipping, 20% import VAT on goods plus shipping plus duty, the carrier's fee for paying them at the border, the total landed cost and the landed cost per unit. It also shows what you pay before the parcel is released.
Who is it for?
UK online sellers who buy stock from suppliers outside the UK, for example from China on Alibaba, and resell it on Etsy, Amazon, eBay, Shopify or at markets. It suits sellers under the £90,000 VAT registration threshold, who cannot reclaim import VAT, and VAT-registered sellers who use postponed VAT accounting.
Why not use a free duty calculator?
Free duty calculators give the duty and VAT for one shipment, and SimplyDuty stops at 5 free calculations a day. They do not add the carrier's own fee (DHL Express UK charges £11.00 or 2.5% of the duty and VAT it pays), and they do not tell you whether that VAT is a cost you keep or one you reclaim, so they cannot give you a price per unit.
What is free and what is in the paid workbook?
Free in the browser: the full answer for one order, with your own goods value, units, shipping, duty rate and carrier fee. The paid .xlsx keeps it: a 25-shipment log with totals for the year, a side-by-side sheet showing the same order VAT-registered and not registered, and the HMRC and carrier rules with the dates they were checked.
How does the price compare with the alternatives?
SimplyDuty gives 5 free calculations a day, then charges £9.99 a month for 100 calculations, up to £99.99 a month for 1,000. A customs broker also charges per entry. This workbook is a one-off payment of $21, not a subscription, and you can run as many orders through it as you like.
When do these rules change next?
HMRC published draft legislation on 13 July 2026 that removes the £135 customs duty relief for low value imports. It comes into force on a date set by the Treasury, by October 2028 at the latest. After that, orders of £135 or less also pay duty; the last result line shows that amount for your order.
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