Free tool
UK CBAM calculator
Check whether your imports pass the £50,000 threshold, then estimate what the UK carbon border adjustment mechanism could cost you from 1 January 2027.
Step 1
Do you pass the £50,000 threshold?
Enter the customs value of UK CBAM goods (aluminium, cement, fertiliser, hydrogen, and iron and steel products) imported in the last 12 months. Only imports from 1 January 2027 count, so during 2027 the look-back starts on that date.
Step 2
Estimate the charge
Add each type of good, the tonnes imported and its embodied emissions in tonnes of CO2e per tonne of product. Ask your supplier for actual figures.
Pre-filled with the official UK carbon price for October 2026 (£63.94) as a stand-in. Official rates use the previous quarter’s average UK ETS auction price.
Final figures not yet published. HMRC’s illustrative worked example uses 87.1% for cement; no other sector’s figure has been published. 0 gives the most cautious estimate. The 2027 factor of 0.975 is applied for you.
Relief may be available for an effective carbon price paid under a qualifying scheme by the installation that made the goods.
Embodied emissions
0 t
Sector rate, net of relief
£63.94
Rate before relief £63.94
Estimated UK CBAM charge
£0
An illustration only, not tax advice. The real charge uses HM Treasury’s published sector rate for the quarter of import, HMRC’s rules on embodied emissions and any relief you can evidence. Get help with your figures.
Calculator questions
How is the UK CBAM charge worked out?
The charge is the embodied emissions of the goods in tonnes of CO2e multiplied by the UK CBAM rate for that sector in the quarter of import, less Carbon Price Relief for any carbon price already paid overseas. The rate is the previous quarter's average UK ETS auction price reduced by the sector's free allocation percentage times a yearly factor (0.975 in 2027).
Who has to pay UK CBAM?
Importers of CBAM goods (aluminium, cement, fertiliser, hydrogen, and iron and steel) whose CBAM imports reach £50,000 over the previous 12 months, or are expected to within the next 30 days. From the date they become registrable, the charge applies to all their CBAM imports, not just the value above £50,000.
What rate does this calculator use?
Until HM Treasury publishes official UK CBAM rates, it starts from the latest official UK carbon price as a stand-in. Official rates use UK ETS auction prices, which can differ, and deduct each sector's free allocation. HMRC's illustrative rates of 16 October 2026, from £1.45 to £9.79 per tCO2e, give an indication of how much lower that makes them. The first real rates are due before the end of 2026. You can enter any price, a sector free allocation percentage and overseas relief.
Where do I get embodied emissions figures?
From your overseas supplier, who should be able to report the actual emissions of the goods. Where actual data is not available, you must use the government's default values, set by HM Treasury notice. The values were published in draft on 16 October 2026 and take effect from 1 January 2027, when the notice is commenced. The law allows them to be set at a level that gives no advantage over verified actual data, so they may be higher than your supplier's real emissions.
Next step
Get real emissions data from your suppliers
Default values may cost you more, and a return filed with them cannot be amended later. Send every supplier a personalised request today.
Want a hand with the real numbers?
Tell us what you import. We will reply within one working day with practical next steps.