HMRC publishes CBAM rates method, default values and emissions guidance

On 16 October 2026 HMRC added a set of CBAM guidance. Rates will be set by sector and change each quarter to reflect the UK carbon price under the UK Emissions Trading Scheme. From 1 January 2027 HMRC will publish them by the start of each quarter. The rate that applies depends on the sector and the quarter in which goods enter the UK.

HMRC also published default values for each sector, in tonnes of CO2 equivalent per tonne of product. Importers can use these in a CBAM return instead of verified actual emissions data. A separate document with illustrative rates and a worked example is labelled illustrative only and creates no tax liability.

Further guidance covers emissions intensity, monitoring by overseas producers and verification. CBAM records must be kept for six years, and a £500 penalty may apply for not keeping them. Regulations on emissions and verification were added on 9 September.