CBAM explained: what EU importers must report and pay, and the emissions data they need from suppliers

What is CBAM?

The Carbon Border Adjustment Mechanism (CBAM) puts a carbon price on certain goods imported into the EU, matching the price EU producers of the same goods pay under the EU emissions trading system. It is set up by Regulation (EU) 2023/956 and covers cement, iron and steel, aluminium, fertilisers, hydrogen and electricity, including many products made from them, such as tubes, screws, bolts and aluminium profiles.

The aim is to prevent carbon leakage: production moving to countries with weaker climate rules, and imports replacing EU goods that carry a carbon price. As EU producers lose their free emission allowances, importers pay a growing share of the same carbon price.

From reports to payment

From October 2023 to the end of 2025, CBAM was in a transitional period: importers reported the emissions embedded in their imports every quarter, but paid nothing. Since 1 January 2026 it is in its definitive period. Importers above the threshold must be authorised, buy certificates for the emissions in what they import, and file a declaration once a year. The first annual declaration, covering imports in 2026, is due by 30 September 2027, and certificates go on sale on a central platform from 1 February 2027.

Who has to comply: the 50-tonne threshold

Since the simplification adopted in October 2025, Regulation (EU) 2025/2083, CBAM obligations only apply to importers that bring in more than 50 tonnes of CBAM goods in a calendar year, counting cement, iron and steel, aluminium and fertilisers together. The Commission expects this to exempt about 90% of importers, mostly small companies and individuals, while still covering about 99% of the embedded emissions. Hydrogen and electricity have no threshold.

An importer above 50 tonnes must be an authorised CBAM declarant before the goods are released into the EU. Importers that applied by 31 March 2026 could keep importing while their application was assessed. A customs representative can act as declarant on the importer’s behalf.

What it costs

One CBAM certificate covers one tonne of CO₂e embedded in imported goods. In 2026 the price is the average auction price of EU emission allowances in each quarter: €75.36 for the first quarter, €75.28 for the second and €82.32 for the third. From 2027 the Commission publishes a price every week. From 2027, declarants must also hold certificates for at least 50% of the emissions imported so far that year at the end of each quarter.

Importers do not pay for the part of the emissions that EU producers of the same goods still receive free allowances for. That free share is phased out: it is 97.5% of the EU benchmark in 2026 and falls each year to zero in 2034, so the bill grows every year. A carbon price already paid in the country of production can be deducted if it is documented.

The emissions data you need from suppliers

The emissions embedded in a good are measured at the installation where it was made. They include the direct emissions of production, the emissions of precursors such as the steel in a screw, and, for cement and fertilisers, the indirect emissions from the electricity used. Producers outside the EU should give you these as actual values per product and installation, calculated with the EU method and checked by an accredited verifier.

Where you cannot get actual values, you use the Commission’s default values per country and product. They carry a mark-up of 10% in 2026, 20% in 2027 and 30% from 2028, or 1% for fertilisers, so missing supplier data costs money.

What may change from 2028

In December 2025 the Commission proposed extending CBAM from 1 January 2028 to about 180 downstream products with a high share of steel or aluminium, such as machinery parts and construction products, together with stricter rules against circumvention. The Council agreed its position with a longer list in June 2026, and the European Parliament adopted its position in September 2026. The final list is now being negotiated, so importers of finished metal goods that are outside CBAM today should follow it.

What to do now

Whether CBAM costs you a lot or very little depends on what you import and on the data your suppliers can give you.

• Add up a year of imports per customs code and check whether the CBAM goods pass 50 tonnes in total.
• If they do, make sure you are an authorised declarant, or that your customs representative acts for you.
• Ask each supplier outside the EU for verified embedded emissions per product and installation.
• Estimate the cost per product with actual values and with default values, to see what better data is worth.
• Budget for buying certificates from February 2027 and for the quarterly holding requirement.

Doing it in Greener Ahead

Greener Ahead does not prepare or file CBAM declarations. Carbon accounting in Greener Ahead calculates your company’s own footprint under the GHG Protocol, where imported steel, aluminium and cement appear in Scope 3 purchased goods, and lets you send your suppliers requests for their emissions figures that they answer in a portal of their own, in their own language. It costs €1,495 per year with unlimited users, and you can try it free for 14 days without a card. Check the pricing page for current details.

CBAM dates to remember

The milestones from the first reports to full payment.

Estimating your exposure

A first estimate needs your import records and a carbon price. For example, 400 tonnes of steel fasteners with illustrative embedded emissions of 2 tonnes of CO₂e per tonne carry 800 tonnes of CO₂e. At €80 per certificate that is a full exposure of €64,000 a year, before the free allocation adjustment that reduces it until 2034.

• Add up a year of imports per customs code.
• Multiply the tonnes by the embedded emissions per tonne, from the supplier or the default value.
• Multiply by a certificate price, such as the €82.32 of the third quarter of 2026.
• Subtract the free allocation adjustment for that good, which shrinks every year until 2034.

Questions to ask a supplier outside the EU

Send these with your purchase orders, so the answers arrive before the declaration is due.

• Which installation made the goods, and where is it?
• What are the embedded emissions per tonne of each product, calculated with the EU method?
• Did an accredited verifier check them?
• What are the emissions of the precursors used, such as the steel or aluminium?
• Was a carbon price paid in the country of production, and can you document it?