| Goods | Commodity code | Net kg | Value | |
|---|---|---|---|---|
| Hot-rolled coil, 2.5mm | 7208 39 00 | 24,000 | £13,200 | ×3.468 = 83.2t |
| Rebar B500, 12mm | 7214 20 00 | 18,000 | £9,900 | ×3.040 = 54.7t |
| Total | 42,000 | £23,100 |
138.0t CO₂e × £9.69 ≈ £1,337
Importing steel or aluminium from January 2027?
From 1 January 2027, steel, aluminium, cement, fertiliser and hydrogen brought into the UK carry a carbon charge. See whether yours do, and roughly what you’d owe, from HMRC’s own figures.
Every one of the 570 codes HMRC has published a default value for, with the government’s illustrative rates. Free, with no account.
When you have to register
CBAM applies to goods imported on or after 1 January 2027. You must register with HMRC once the CBAM goods you import meet or exceed £50,000 in value, on either of two tests: the imports you expect over the next 30 days, or the imports over the 12 months before the first day of any month.
Registration opens on 1 January 2028. If you pass the threshold during 2027 you have until 31 January 2028; after that, 30 days from the day you pass it. Your first return covers every CBAM import from January to December 2027, and it and the payment are due by 31 May 2028. A tax agent can send your returns, but can’t register for you, and the tax stays yours.
Source: HMRC, CBAM policy summary, updated 2 November 2026.
HMRC’s default values, or your supplier’s figures
The charge is worked out from each good’s embodied emissions. You can use verified emissions data from the mill or smelter that made it, checked by a qualifying verifier, which HMRC calls the preferred option. Or you can use HMRC’s default value for its commodity code, which is the same whichever country it came from.
A return that uses default values can’t be amended later with actual data. So the time to ask your suppliers for verified figures is before your first imports in January, not when the return is due.
Sources: HMRC, default values, 16 October 2026; getting the emissions intensity.
The rates, and why they’re only a guide for now
Each sector has its own rate per tonne of CO₂e, worked out from the UK Emissions Trading Scheme price less the share of free allowances UK producers still get. The government publishes them at the start of each quarter from 1 January 2027; the first will be out before the end of 2026. Its illustrative rates, from the July to September 2026 price of £58.15, are:
- Iron and steel£9.69
- Aluminium£9.79
- Cement£8.78
- Fertiliser£1.45
- Hydrogen£9.24
Source: GOV.UK, illustrative CBAM rates and worked example, 16 October 2026.
The return, with every supplier’s figures in it
We’re building the rest: a request to each supplier for verified emissions data, a record of every CBAM import as it arrives, and your first return worked out and ready to send by 31 May 2028. Join the waiting list and we’ll email you once, when it’s ready.
Questions
What is the UK CBAM?
The Carbon Border Adjustment Mechanism is a tax on the carbon emitted in making certain goods imported into the UK, so that they face a carbon price like goods made here. It applies to aluminium, cement, fertiliser, hydrogen, and iron and steel imported on or after 1 January 2027, including into Northern Ireland.
Do I need to register for UK CBAM?
You must register with HMRC if the CBAM goods you import meet or exceed £50,000 in value: either over the coming 30 days, or over the 12 months before the first day of any month. Registration opens on 1 January 2028. Anyone who becomes liable during 2027 has until 31 January 2028 to register.
When is the first UK CBAM return due?
The first return, and the payment, covers imports from 1 January to 31 December 2027 and is due by 31 May 2028.
How is the CBAM charge worked out?
The embodied emissions of each good (its emissions intensity in tonnes of CO2e per tonne, times its weight) multiplied by the CBAM rate for its sector and the quarter it was imported, less any relief for a carbon price already paid abroad. The government publishes the rates at the start of each quarter from 1 January 2027.
What are CBAM default values?
Figures HMRC publishes for each CBAM good, in tonnes of CO2e per tonne, which you can use instead of verified emissions data from your supplier. They apply whatever country the goods come from. A return that uses default values can’t be amended later with actual data, so it’s worth asking suppliers for verified figures first.
What will the CBAM rate be in 2027?
It isn’t set yet. The government’s illustrative rates, worked from July to September 2026 data, are £9.69 per tonne of CO2e for iron and steel, £9.79 for aluminium, £8.78 for cement, £1.45 for fertiliser and £9.24 for hydrogen. The rates for January to March 2027 will be published before the end of 2026.
Can my customs agent do CBAM for me?
A tax agent can submit your CBAM returns, but can’t register for you, and the liability stays with you as the importer.
Is the checker free?
Yes, with no account. It uses HMRC’s published default values and the government’s illustrative rates, so the charge it shows is a guide, not your liability.