Guides / DUCR explained · Updated 19 October 2026

DUCR number explained: meaning, format and where it is used

A DUCR is the reference every UK export declaration in CDS must carry. It is created by the trader, not by HMRC, and it follows the goods from the declaration to the loader, the GMR and your VAT records. Here is what the DUCR number means, how HMRC wants it built and where it is used.

This guide is also available in Polish.

DUCR meaning: what the reference is for

DUCR stands for Declaration Unique Consignment Reference. In the UK's Customs Declaration Service (CDS), it is the reference that ties an export declaration to a physical consignment. HMRC's export completion guide makes it mandatory: every declaration must carry a DUCR, it must be unique, and it is declared in data element (DE) 2/1 using the previous document type code DCR.

The key point about a DUCR number is that nobody at HMRC issues it to you. The final part of the reference is a series the trader devises for its own audit trail, so the DUCR is built on the exporter's or agent's side and goes into the declaration when it is lodged. It is a different number from the Movement Reference Number (MRN) attached to the same declaration. If you are unsure which of the two you are holding, our guide to MRN numbers sets out the difference from the haulier's side.

The DUCR number format HMRC recommends

HMRC states that the recommended format of the DUCR in the UK is the World Customs Organization format. It has five parts, written as one string with no spaces:

Put together, HMRC's Great Britain example reads 5GB000000000000-12345 and its Northern Ireland example 5XI000000000000-12345. A reference allocated this year therefore starts with 6.

EU businesses exporting from the UK meet one extra rule. HMRC says an EU EORI should have 12 characters after its country code: shorter numbers are padded with zeros at the end, and longer ones are cut to the first 12 characters. HMRC's example for a French EORI in 2026 is 6FR123456789000-12345. HMRC's guidance does not set an overall maximum length for the DUCR, so check the validation rules in your declaration software rather than relying on a figure you have seen elsewhere.

Part numbers, DE 2/4 and licences

For exports, HMRC requires the MUCR, the DUCR and the DUCR part number to be declared at header level. Part numbers matter most when a supplementary declaration covers several initial declarations: the DUCR and part of the first initial declaration go at header level, and those of the others are added as separate previous documents with the code DCS.

Two further details cause avoidable rejections:

• DE 2/4 is not a substitute. DE 2/4 is an optional field for the declarant's own commercial reference. It may follow the DUCR format, but for exports the MUCR and DUCR must still be declared in DE 2/1.
• Electronic licences must match. Where goods move under an electronic licence, HMRC requires the DUCR entered in CDS to match the one recorded on the licence.

DUCR, MUCR and consolidation

Groupage and air freight often move many export declarations as one shipment. That is what the MUCR (Master Unique Consignment Reference) is for. HMRC's rules are short:

• Only one MUCR may be declared on an export declaration, at header level, with the code MCR.
• A MUCR can hold one or many DUCRs, but a DUCR can belong to only one MUCR.
• MUCRs can themselves be associated with other MUCRs.
• The MUCR follows the commercial conventions of the traffic type. For air freight it is normally the master or simple air waybill number.
• If a MUCR is entered, a CDS message must also be sent to close the consolidation.

At ports and airports, authorised loaders report when exports arrive and depart. HMRC's service for doing this asks for the DUCR, plus the MUCR if the goods were consolidated into a bigger consignment, so the references you put on the declaration are the ones the loader will look for.

The DUCR in GVMS for Great Britain to EU journeys

At ports using the Goods Vehicle Movement Service, the haulier links the vehicle to the customs declarations through a goods movement reference. For goods leaving Great Britain for the EU and declared into CDS, GOV.UK says the GMR should carry the DUCR for the combined customs and safety and security export declarations, and multiple declarations can be added. For goods leaving under common transit, the GMR carries all the DUCRs if the authorised consignor does not meet the criteria to use a Transit Accompanying Document MRN.

In practice, the exporter or agent should send the haulier every DUCR on the load before the vehicle sets off. Our step-by-step guide to creating a GMR shows where the references go.

Why the DUCR matters for zero-rated VAT

For UK VAT, HMRC's Notice 703 treats official evidence of export as an export declaration submitted to CDS that has generated a departure confirmation, and says you will need the MRN or the DUCR of that declaration. For direct exports, the notice gives three months to export the goods and obtain valid evidence. A DUCR that never reached the GMR or the loader is one of the ways a departure can go unconfirmed, so keep each DUCR with the invoice it relates to.

For a shorter worked example from a customs agency's perspective, including how agents ask clients for the reference, see DUCR numbers explained.

DUCR checklist for exporters

• Each declaration has its own unique DUCR in DE 2/1, code DCR.
• The year digit is a single number for the year of allocation.
• The EORI part matches the trader HMRC knows, padded to 12 characters for an EU EORI.
• The trader reference uses only numbers, upper-case letters and permitted characters.
• Consolidated goods have one MUCR, and the consolidation has been closed.
• The haulier has every DUCR for the GMR before departure.
• The DUCR is filed with the invoice and the departure confirmation for VAT.

Related guides

• Shipping goods from Germany to the UK: customs step by step

• Polish AES export procedure: export declarations from Poland to the UK

• How remote customs clearance works for UK–EU shipments

Sources

• CDS Volume 3 export declaration completion guide, Group 2: references (GOV.UK)
• Get a goods movement reference (GOV.UK)
• Tell HMRC when exports have arrived or departed a UK port (GOV.UK)
• NTE 2024/19: Customs Declaration Service exports, important information (GOV.UK)
• VAT on goods exported from the UK, Notice 703 (GOV.UK)

General information, not legal, tax or customs advice. Rules change; confirm current requirements on gov.uk or with a registered agent before you ship.