HMRC has set out draft emissions values for imported goods in five sectors, to apply from 1 January 2027 for importers without verified emissions data.
The UK HM Revenue & Customs (HMRC) has published a draft force of law notice setting default values for the UK carbon border adjustment mechanism (CBAM) on 16 October 2026. The default values let liable persons comply with CBAM when actual verified emissions data for imported goods is unavailable.
They will be in force from 1 January 2027 to 31 December 2028.
Why default values matter
The government says actual verified emissions data remains the preferred basis for UK CBAM. Default values exist as a fallback so that importers can still meet their obligations.
The guiding principle is to protect the environmental integrity of CBAM. Using a default value should give a liable person no advantage over determining the actual embodied emissions of imported goods.
How the values were set
The UK values are based on EU data, calculated to reflect the same CBAM system boundaries as the UK. They are set on a trade-weighted average basis, so they reflect the composition of UK imports.
Data from the EU is excluded. According to the notice, this helps the values better reflect the goods for which defaults are most likely to be used. It also recognises the UK and EU commitment to link their emissions trading schemes, which will result in EU-origin goods being exempt from UK CBAM.
Markup and sector exemption
A markup is applied to the default values. The government says this balances support for CBAM objectives with the transition to actual emissions reporting.
A markup of 10 per cent applies in all sectors except fertiliser, where no markup is applied.
Values by sector
Each value is expressed in tonnes of carbon dioxide equivalent (tCO2e) per tonne of product and is listed against a Combined Nomenclature (CN) code. The notice covers five sectors.
Aluminium: Values run from 2.030 tCO2e per tonne for unwrought aluminium alloy billets to 6.023 tCO2e per tonne for aluminium composite panel of a thickness of 0.2mm or less. Unwrought aluminium slabs, not alloyed, are set at 2.058 tCO2e per tonne.
Cement: Values range from 0.240 tCO2e per tonne for kaolinic clays (other than kaolin) to 2.075 tCO2e per tonne for aluminous cement. Cement clinkers are set at 1.433 tCO2e per tonne, and Portland cement (excluding white) at 1.375 tCO2e per tonne.
Fertilisers: The lowest value is 0.457 tCO2e per tonne, for certain urea in aqueous solution. The highest is 3.247 tCO2e per tonne, for sodium nitrate. Anhydrous ammonia is set at 2.434 tCO2e per tonne and nitric acid at 2.048 tCO2e per tonne. These figures carry no markup.
Hydrogen: A single value of 28.378 tCO2e per tonne applies to hydrogen. It is the highest figure in the notice by a wide margin.
Iron and steel: This is the largest category. Values range from 0.494 tCO2e per tonne for agglomerated iron ores and concentrates to 9.121 tCO2e per tonne for certain hot-rolled stainless steel flat products in coils. Non-alloy pig iron falls between 1.331 and 2.698 tCO2e per tonne depending on its composition.
Stainless and alloy steel products generally carry higher values than non-alloy products.
Move to country-specific values from 2029
The current values are a single set applying across all origins. From 2029, the UK will move to country-specific default values, with one default value per CBAM good per country.
The government says this will give a more granular and accurate reflection of the emissions embodied in CBAM goods. The appropriate level of markup will be reviewed at that time.
The values will also be updated in due course, as necessary, to account for any future changes to the Combined Nomenclature system.
Legal basis
The notice is made under primary legislation. The text has the force of law by virtue of paragraph 11(1) of Schedule 17 to the Finance Act 2026.
HMRC advises users to search the CN code on their device to find the relevant default value. Importers and customs agents will need to match their goods to the correct code, since the value applies to the product as classified.
Earlier, HMRC issued draft regulations on the carbon border adjustment mechanism (CBAM) on 9 April 2026.
