UK updates national additional codes for customs declarations
HMRC has published updated national additional codes for use in Data Element 6/17 of the Customs Declaration Service (CDS). These codes are required to calculate duties and taxes correctly on UK imports and exports. Shippers and customs brokers using CDS must reference Appendix 19 for the current code set to ensure accurate duty and tax calculation on all declarations.
Photo: Bibek ghosh / PexelsHMRC publishes updated national additional codes for CDS
On 1 May 2026, the UK's HM Revenue & Customs (HMRC) released guidance on national additional codes to be declared in Data Element 6/17 of the Customs Declaration Service. These codes are mandatory declarations required to calculate duties and taxes correctly under UK customs law.
Who this affects
This guidance applies to anyone filing customs declarations through CDS:
- UK importers and exporters
- Customs brokers and freight forwarders
- Registered traders with import or export obligations
Data Element 6/17 is a structured field in CDS declarations where traders must enter the appropriate national additional code relevant to their goods and transaction. The code selected directly impacts duty assessment and tax calculation.
What you need to do
HMRC states: "Find the national additional codes to be declared in Data Element 6/17 to calculate duties and taxes (Appendix 19)." Traders must:
- Consult Appendix 19 of the guidance for the complete list of current national additional codes
- Identify the correct code(s) that apply to each line item in a customs declaration
- Enter the code(s) in Data Element 6/17 when submitting the declaration
The codes cover a range of goods classifications, relief categories, and origin designations. Incorrect or missing codes can result in:
- Incorrect duty calculation
- Tax assessment errors
- Customs penalties and delays
- Declaration rejection by CDS
Traders should cross-reference the commodity code (HS classification) against the national additional codes table to ensure the right supplementary information is provided. This is particularly critical for goods benefiting from preferential treatment, exemptions, or subject to additional levies.
What this means for shippers
Your CDS declarations require the correct national additional codes in Data Element 6/17 to clear customs without delays or duty errors. Pull the latest Appendix 19 from HMRC's guidance immediately and update your internal HS code and declaration templates. Failing to use current codes risks rejections, recalculations, and penalties. Use our HS classification tool to verify commodity codes align with the correct national additional codes.
