How is a UK CBAM emissions intensity calculated?

Take one calendar year of verified direct emissions for the product, convert N2O and PFCs to CO2e (N2O 265, CF4 6,630, C2F6 11,100), add precursor emissions, and divide by tonnes produced, rounded to 5 decimal places. The importer multiplies that intensity by the tonnes imported.

HMRC's eight steps

1. Identify the monitoring period: one calendar year.
2. Attribute the installation's verified emissions to the CBAM good, using the system boundaries and monitoring method.
3. Convert non-CO2 gases: N2O x 265, CF4 x 6,630, C2F6 x 11,100.
4. Add CO2 and CO2e together.
5. Add precursor emissions: precursor tonnes used times their intensity or default.
6. Find the tonnes of the good produced in the period.
7. Divide step 5 by step 6, rounded to 5 decimal places.
8. The importer multiplies the intensity by the weight imported.

Rounding

Record values to up to 5 decimal places while calculating. Total embodied emissions are reported rounded to the nearest whole tonne of CO2e, and only after all calculations are done.

Worked example: aluminium ingot line

• Direct CO2 for the year: 12,000 t.
• CF4 0.5 t x 6,630 = 3,315 tCO2e. C2F6 0.06 t x 11,100 = 666 tCO2e.
• Total: 12,000 + 3,315 + 666 = 15,981 tCO2e; no precursors.
• Output 7,500 t: 15,981 / 7,500 = 2.13080 tCO2e per tonne.
• Buyer imports 400 t: 400 x 2.13080 = 852.32, reported as 852 tCO2e.

What Senseible does here

Senseible reads fuel, material and precursor invoices into the inputs for steps 2 and 5. We build the figure from your records and check every figure in-house; for the UK it must then be verified by a verifier accredited for UK CBAM. Have your own verifier? Send it to them.

• Embedded emissions for steel
• Gases beyond CO2

Sources: HMRC, Carbon Border Adjustment Mechanism (CBAM): Policy summary (updated 2 November 2026), HMRC, UK CBAM monitoring, reporting and verification technical guidance (October 2026)

Last reviewed 2026-11-02.