Our European Union (EU) buyer was under 50 tonnes of Carbon Border Adjustment Mechanism (CBAM) goods until October. Do its earlier imports that year count once it passes 50?

Yes. Under the Commission's Guidance No. 1, an importer that exceeds the single mass-based threshold in a calendar year becomes subject to all CBAM obligations for that year, covering the emissions embedded in all goods imported during that year, including those imported before the threshold was exceeded.

What the guidance says

• The threshold is 50 tonnes of net mass. It applies to the aggregate net mass of all goods, across all Combined Nomenclature (CN) codes, imported by the same importer within the same calendar year.
• Where the exemption applies, the importer must indicate the exemption in the relevant customs declaration.
• If the importer exceeds the threshold during a calendar year, it or its authorised CBAM declarant becomes subject to all CBAM obligations for that calendar year, including for goods imported before the threshold was exceeded.

What adds to the 50 tonnes

• Returned goods of non-EU origin under Article 203 of the Union Customs Code count, even though their embedded emissions are declared as zero (Questions and Answers (Q&A) 7.19).
• For a metal part assembled with another material under a CBAM code, the net mass of that CN code in the customs declarations is counted (Q&A 4.30).
• Hydrogen and electricity are not covered by the exemption at all (Guidance No. 1).

Customs codes on the way up

Customs document codes Y128 and Y137 for an importer near the line are covered on the linked page (Questions and Answers 7.22).

What it means for you

Our reading: the shipments from January to September need the same data as the ones after October, because the whole year counts. Keep your production records and installation data for the full year, and ask the buyer for a running total each quarter. It is the buyer that holds the count, since it covers all of the buyer's suppliers.

A buyer's year, in tonnes (our example)

• February 18 + May 12 + August 10 = 40 tonnes, under 50, so exempt so far
• October 20 more: 40 + 20 = 60 tonnes, which is 10 above the threshold
• The obligations cover all 60 tonnes of the year, not only the 20 tonnes of October and not only the 10 tonnes over the line

Example numbers only. The rule is the Commission's wording quoted above.

What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records. It does not decide an importer's CBAM position, it is not a CBAM verifier and it does not file declarations.

• How the 50 tonne threshold is counted
• Customs codes Y128 and Y137
• Returned goods and the 50 tonnes
• Check your buyer is an authorised declarant
• CBAM for Indian exporters

Sources: European Commission, Guidance No. 1, Introduction to CBAM concepts, section 2.5 (de minimis exemption), European Commission, CBAM Questions and Answers (updated 15 October 2026), questions 4.30, 7.19 and 7.22

Last reviewed 2026-11-06. The Commission reviews the threshold against a 1% share of embedded emissions each year, so re-check the 50 tonne figure when a new assessment is published.