UK CBAM, answered plainly
Straight answers on scope, dates and cost, each traceable to the gov.uk sources on our sources page. The confirmed-versus-pending picture is kept live on the CBAM Rulebook Status board.
When does the UK CBAM start?
It takes effect and starts charging from 1 January 2027. Unlike the EU, which ran a report-only period first, the UK has no transitional reporting-only phase: the charge applies from day one of the first accounting period.
Which sectors and goods does it cover?
Five sectors: aluminium, cement, fertiliser, hydrogen, and iron and steel. Glass and ceramics are excluded at launch and electricity is not in scope. Scope is set by specific commodity (CN) codes; aluminium scrap (heading 7602) and ferrous waste and scrap (heading 7204) are named exclusions. The definitive CN list is set by secondary legislation and is still being finalised.
What is the £50,000 threshold and how is it measured?
You must register once the value of the CBAM goods you import meets or exceeds £50,000. It is a rolling test with two limbs: a 30-day forward look (on any day, do you expect to import £50,000 or more of CBAM goods over the next 30 days) and a 12-month backward look on the first of each month. It is measured on the value of the goods, not on the emissions or the charge.
Who has to register and pay?
The liable person is the one importing the CBAM goods for commercial purposes, in practice the person in whose name the customs declaration is made, or their representative. That person registers, files returns and pays.
When must I register?
Ordinarily within 30 days of becoming liable. During the first year there is an easement: businesses have until 31 January 2028 to register.
When is my first return and payment due?
31 May 2028, covering the first accounting period of 1 January to 31 December 2027. From 2028, accounting periods become quarterly, with the exact 2028 deadlines being finalised in secondary legislation.
How is the charge calculated?
Embodied emissions (tCO2e) multiplied by the sector rate for the quarter (£ per tCO2e), minus relief for any qualifying overseas carbon price already paid. You may use a published default emissions value or your supplier's actual verified data.
What is the CBAM rate, and is it known yet?
It is set and published quarterly from 1 January 2027, based on the average UK ETS auction price for the preceding quarter, adjusted down for the free-allowance share in that sector. An illustrative example rate is expected in Autumn 2026. Until an official figure exists, our estimator uses a clearly labelled illustrative rate, never one presented as official.
Can I reduce the charge?
Two ways. Use your supplier's actual, independently verified emissions instead of the default value, because defaults carry a mark-up and a cleaner producer usually pays less on actual data. And claim overseas carbon price relief where a qualifying carbon price has already been paid abroad, with documentary evidence and HMRC-published exchange rates.
Is the UK CBAM the same as the EU CBAM?
No. They are different regimes with different thresholds, a different rate basis, and different timing. The UK has no transitional reporting-only phase, sets its rate from the UK ETS price, and uses its own £50,000 threshold. If you import into both, you are dealing with two separate sets of rules.
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