Do I need a CN23 for my Shopify parcel?

Only when you send goods by post across a customs border, for example from the EU to the UK, Switzerland, Norway or the US, or from the UK to the EU. And when you buy the postage online, the postal operator usually makes the form for you. This article explains when a CN22 or CN23 is needed, which one, and what to check.

This article isn't legal or tax advice. Your postal operator's rules decide; check them when in doubt.

When a postal customs form is needed

• Goods sent by post across a customs border. Leaving the EU or the UK, or going into them.
• Some territories inside a country, such as the Canary Islands or the Channel Islands, are outside the customs or VAT area too, and need a form.

Not needed:

• Within the EU, between EU countries, or within the UK.
• Documents with no commercial value, such as letters.
• Express couriers such as DHL, UPS and FedEx. They don't use the CN22 or CN23; they ask for a commercial invoice instead.

CN22 or CN23

Both are customs declarations from the Universal Postal Union, the body that sets the rules for international post.

• CN22: a short form for low-value items. The UPU limit is 300 SDR, about £270 or €350.
• CN23: the full form, for anything over that, and for parcels that a postal operator always declares in full.

Postal operators add their own rules. PostNL, for example, asks for a CN23 on parcels outside the EU and allows a CN22 only on untracked parcels up to 2 kg. Royal Mail uses a CN22 up to £270 and a CN23 above. When you buy postage online, the operator picks the right form.

The official CN23 comes with your label

When you buy an international postal label online, or at a post office counter, you enter the customs data for each item. The postal operator sends that data to customs electronically, ahead of the parcel, and prints the official CN22 or CN23 with the label. Since 2025, postal operators send this data electronically for every parcel; the paper form still travels with it.

So the quality of the form depends on what you type in. For each item, the form asks for:

• a description customs understands ("Ceramic coffee mug", not "Gift"),
• the quantity, net weight and value,
• the HS code and the country of origin,
• the category: sale of goods, gift, sample, returned goods and so on.

PostNL warns that it holds parcels whose forms are incomplete, even when a field doesn't look mandatory.

Do I also need an invoice?

Often, yes, for a sale. Customs officers read the invoice when they open the parcel, and some postal operators ask for copies in a pouch on the outside. An invoice is also where a statement on origin goes, for zero duty between the EU and the UK. See Which document do I need?

How Borderdesk helps

Borderdesk is a Shopify app for EU and UK shops that ship across the border.

• It keeps the HS code, country of origin and customs description on every product complete, in Shopify's own customs fields. Label apps that read those fields fill in the CN23 data for you.
• It prints a supporting copy of the CN23 for each order, to keep as a record, pack with the parcel or copy from when you fill in the operator's form.
• It prints commercial and pro forma invoices to go with it.

Borderdesk on the Shopify App Store

Sources

• PostNL, customs forms
• European Commission, ICS2 for postal and express parcels