CN22 & CN23 Explained

CN22 and CN23 are customs declaration documents that detail the contents of a package being sent outside of the EU when being sent through the Royal Mail. They assist the process customs go through when checking packages, and they detail important information about the contents of anything being posted. 

Any letter or parcel that is considered to contain ‘commercial value’ requires a CN22/23, as these items are subject to fees and taxes. For example, if you’re sending a letter to a pen pal who lives in Beijing, you do not need to include a customs declaration form*. However, if you’re sending this same friend a gift or parcel, you do need to attach the appropriate CN22/23 form.

*Please note: If you're using UK Postbox to send a letter with no monetary value outside of the EU, we will require that you complete a CN22 before sending.

With Brexit upon us, it’s pivotal that importers and exporters are aware of what they are, how to correctly complete them, and where you can get them from. This is because once the UK leaves the EU, any mail items being sent to European countries through the Royal Mail will require a CN22/23. 

Difference between CN22/23 and commercial invoices

CN22 and CN23 documents are exclusively required when sending goods to the EU when shipping through the Royal Mail. International couriers such as DHL or DPD do not require a CN22/23, but rather a Commercial Invoice. The information and use of this invoice functions similarly to CN22/23, but make sure you complete the correct form for your preferred shipping option. 

Why are they needed?

  1. They assist customs in checking the contents of packages leaving the EU via the Royal Mail.
  2. They help customs to assign the correct duties and charges that need to be applied.
  3. The forms aid in the monitoring of prohibited goods being shipped.


Must be used if your goods are being transported outside of the EU, up to the value of £270*


If the value of your goods being transported outside of the EU have a value of over £270, then a CN23 is needed instead of a CN22*

*Note: When the UK leaves the European Union, any mail being sent to the EU from the UK will require a CN22/23 attachment when being sent through the Royal Mail.

What information you’ll need to include 

You must complete your CN22/23 fully and honestly. The sender of the package is legally responsible for the customs declaration, and the sender of the package must sign it.

Any misinformation or lack of completing can result in delays in processing, mail return or seizure by customs authorities. It’s essential that you truthfully and accurately declare the items being sent. Here’s everything you should prepare for your CN22/23 customs declaration form:

  • A detailed description of your product - do not be vague, make it easy for customs to read and understand what you’re sending
  • The quantity of goods being sent within the package, i.e. if you’re mailing 10 steering wheel covers, you must detail ‘10 steering wheel covers’.
  • The weight of the contents given in Kilograms.
  • The value of the contents, given in the currency you use.
  • Harmonised Code - a set of digits that categorise what your goods are and the category they belong to. This is used to assist customs in applying the correct fees and charges. Harmony Codes will become a necessity for sending goods abroad in the near future, so it’s important that you understand what they are and accurately include this information on anything you send. You can find information about your code through the government trade tariff look up.
  • The country of origin.
  • A signature of the sender, and the date that the CN22/23 was signed.

Note: If you are unable to complete your customs declaration in English or French, then you will need to use the native language of the destination country.

Where do you include your CN22/23

As the CN22/23 customs declaration needs to be inspected for processing, it should be attached to the outside of the parcel in a protective sleeve as to avoid any damage. Failure to do so will only result in your package being inspected, held, delayed or seized.

Where can you get a CN22/CN23

If you need a CN22 or CN23 document, these are available at your local Post Office or available online through the Royal Mail.

CN22/CN23 through UK Postbox

If you require a CN22/23, we offer the service within our mail management app. UK Postbox requires that all mail being sent outside of the EU require an attached CN22, regardless of whether it is of commercial value or not. While this isn't a legal requirement, we believe that this will become mandatory after Brexit, and therefore we have taken the decision to implement this practice now. When you’re sending a letter or parcel outside of the EU, we’ll also ask you to complete all of the required CN22/23 information before we post it on your behalf. 

For example, if you’re using our Fulfilment and Dropshipping Services and need a parcel sent to a customer outside of the EU, your shipment will require a CN22/23. When you let us know that you need a parcel posted, you’ll be asked to provide the relevant information to complete your declaration. Once we have everything needed, we’ll attach it to your parcel for you before sending.


When the UK leaves Europe, our app will be updated to reflect the need for CN22/23 and commercial invoices when sending parcels to European Countries. We’ll ensure this up to date for you; you’ll simply receive a prompt that a customs form needs completing.

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Allan Chester
September 6, 2019