Which UK imports the carbon border tax hits, and how big the bill gets
From 1 January 2027 the UK CBAM covers five sectors: iron and steel, aluminium, cement, fertiliser and hydrogen. Those five move roughly US$15 billion of imports into the UK every year. Here is the scale by sector, where the goods come from, and what the government itself forecasts the charge will raise.
Combined latest annual UK import value of iron and steel, aluminium, cement, fertiliser and hydrogen. Iron and steel plus aluminium alone are about 88% of it. Hydrogen is under US$10 million, a rounding error next to the metals.
Government forecast for CBAM receipts across its first four years, 2027 to 2031. Source: gov.uk CBAM impact assessment.
UK businesses import goods in the CBAM sectors, on HMRC's estimate. Most will owe nothing once the threshold applies.
Share of otherwise affected importers lifted out of the charge by the £50,000 threshold. Over 70% of those removed are SMEs.
Two metals carry almost the entire flow
The carbon border charge is often discussed as five equal sectors. By import value it is nothing of the kind. Iron and steel and aluminium each bring in about US$6 to 7 billion a year, while fertiliser is a fifth of that, cement smaller again, and hydrogen barely registers. That matters because the eventual bill scales with the value and the emissions of what crosses the border, so the metals are where the money and the compliance effort will concentrate.
UK imports by CBAM sector, latest available year
Value of goods imported into the UK, US dollars, billions. UN COMTRADE.
How to read this: each bar is one sector's total UK import value for the latest year published. Longer means more goods, by value, crossing the border. Hover or tap a bar for the figure and the note.
Source: UN COMTRADE (via Trading Economics and IndexBox), latest available annual data. Iron and steel 2025; aluminium, fertiliser, cement and hydrogen 2024. Figures are broad trade groupings; CBAM applies only to specific commodity codes within each sector, so the charged flow is smaller than the totals shown. Read this as relative scale.
Show the numbers
| Sector | Import value (US$) | Year |
|---|---|---|
| Iron and steel | 7.02 bn | 2025 |
| Aluminium | 6.22 bn | 2024 |
| Fertiliser | 1.20 bn | 2024 |
| Cement | 0.56 bn | 2024 |
| Hydrogen | 0.008 bn | 2024 |
Most of it already carries a carbon price. The growth is in supply that does not.
The single most important origin fact for importers is the government's own: about four in five CBAM goods come from countries that already run a carbon price. Where a qualifying overseas carbon price has been paid, it reduces the UK charge, so origin drives the bill as much as volume. The tension the policy is built around is that the fastest-growing supply, Turkish cement, North African and Middle Eastern fertiliser, non-EU steel, often comes from places with no equivalent price.
of CBAM goods imported into the UK come from countries that already have a carbon pricing system, on the government's estimate. That is why overseas carbon price relief is built into the charge, and why proving what you have already paid abroad is worth the paperwork. Source: gov.uk CBAM impact assessment, as at 12 July 2026.
Iron and steel
Share of UK steel imports, 2024. EU is about two thirds.
UK Steel key statistics and HMRC trade data. Leading EU sources named; Asian origins growing.
Cement
Main suppliers. Imports are about 30% of the UK market (3.6m tonnes).
Mineral Products Association and IndexBox market data. Turkish supply grew about 240% from 2024 to 2025.
Fertiliser
Leading suppliers by volume, 2024. Top three are about 40% combined.
AHDB and UN COMTRADE. Supply has shifted toward the Middle East and Americas as EU gas costs rose.
Hydrogen
Share of UK hydrogen imports, 2024. Two neighbours dominate a tiny flow.
UN COMTRADE. Total UK hydrogen imports were about US$8 million in 2024, a fraction of the other sectors.
Carbon-price labelling is indicative, based on whether the country operates a recognised emissions trading scheme or carbon tax. It signals where overseas carbon price relief is most likely, not a guarantee. Aluminium origins are more mixed across the EU, the Gulf and Asia and are not shown as a single ranking.
The £50,000 threshold lifts most importers straight out
Ten thousand businesses import goods in these sectors, but the charge is aimed at the volume, not the long tail of small importers. HMRC estimates that the £50,000 registration threshold removes more than 80% of otherwise affected importers, and that more than seven in ten of those removed are SMEs. The result is a charge that lands on a smaller group of larger importers, while a container or two a year of steel fixings or aluminium extrusions usually falls below the line.
Of every 100 otherwise affected importers, who stays in scope
Each square is one importer in 100. Shaded by whether the £50,000 threshold removes them.
How to read this: 100 squares stand for the importers who would otherwise be caught. The pale squares are lifted out by the threshold; the teal squares stay in. Applied to the roughly 10,000 importers, fewer than about 2,000 are left liable, and over 70% of those lifted out are SMEs.
Source: gov.uk CBAM impact assessment (over 80% of otherwise affected importers excluded; over 70% of those removed are SMEs; about 10,000 businesses affected). As at 12 July 2026.
The government forecasts £650 million over four years
The Exchequer impact published with the policy puts CBAM receipts at £140 million in 2027 to 2028, rising to a peak of £180 million the year after, then easing back toward £155 million by 2030 to 2031. The dip is expected: as the charge bites, some supply shifts to cleaner producers or to origins that already price carbon, which is the point of the policy rather than a flaw in it.
Forecast UK CBAM receipts by financial year
Exchequer impact, £ millions. Positive figures are revenue to the government.
How to read this: each bar is one financial year's forecast receipts in £ millions. Hover or tap a bar for the figure. The four bars sum to £650 million.
Source: gov.uk, Carbon Border Adjustment Mechanism policy paper, Exchequer impact table. As at 12 July 2026.
Show the numbers
| Financial year | Forecast receipts |
|---|---|
| 2027 to 2028 | £140m |
| 2028 to 2029 | £180m |
| 2029 to 2030 | £175m |
| 2030 to 2031 | £155m |
| Four-year total | £650m |
What a single importer might face, and why we will not pretend to know yet
The official rate and the per-good emissions defaults are not published yet, so any per-consignment number today is illustrative. Here is the method the charge will use, with clearly flagged illustrative inputs, so you can see the shape of a bill without us inventing the constants.
- Tonnes imported in the year
t1,000 t - Embodied emissions factor
tCO2e per t2.0illustrative, near the global average for crude steel; official default pending - Embodied emissions
t x factor2,000 tCO2e - CBAM rate
£ per tCO2e~£40illustrative, near the recent UK ETS auction price; the real rate is adjusted down for free allowances and is unpublished - Gross charge
emissions x rate~£80,000 - Less any qualifying overseas carbon price already paidreduces the netdepends on origin and evidence
This panel exists to show the method, not to quote a price. Every constant above is a clearly labelled illustrative placeholder. The actual CBAM rate is set quarterly from the UK ETS price adjusted for free allowances, with a government example expected in Autumn 2026, and the per-good emissions defaults are published separately. Using your supplier's actual verified emissions usually lowers the charge below the default. Nothing here is tax advice.
CBAM rulebook status
The policy architecture is confirmed. The numbers you multiply, the final commodity list, the emissions defaults and the quarterly rate, are still landing in secondary legislation through 2026. This board separates the two, so you know which figures on this page are fixed and which will move.
Confirmed vs still in consultation
Each status carries a text label, not colour alone. As at 12 Jul 2026.
Start date 1 Jan 2027, charging from day one
Five sectors: steel, aluminium, cement, fertiliser, hydrogen
£50,000 registration threshold
Forecast receipts £650m across 2027 to 2031
Final commodity-code (CN) list of in-scope goods
Per-good default emissions values
Quarterly CBAM rate (illustrative example)
We update this board as the rules land. Full citations on the sources page.
How this was put together, and what to be careful about
Method
Import values by sector are the latest annual figures from UN COMTRADE, the standard international trade database that UK data also feeds, taken at the broad trade grouping for each sector. Iron and steel is the most recent published year (2025); aluminium, fertiliser, cement and hydrogen are 2024. The four-sector share bar and the US$15 billion headline are the sum of these figures.
The receipts forecast, the 10,000 businesses, the 80% threshold exclusion, the SME share and the 80% carbon-priced origin figure are all taken directly from the government's published CBAM material. Origin breakdowns come from the named trade bodies and databases for each sector.
Honest caveats
These sector totals are broad groupings. CBAM applies only to specific commodity codes and names exclusions such as scrap, so the actually charged flow is smaller than the bars shown. The final code list is still in consultation.
The cost example is illustrative only. The official CBAM rate and per-good emissions defaults are not published as at 12 July 2026, so no figure here should be read as an official price. Where years or trade groupings differ between sectors, read the sector chart as relative scale rather than a precise league table. This is general information, not tax advice.
Sources
- GOV.UK Carbon Border Adjustment Mechanism policy paper (forecast receipts by year, 10,000 businesses, over 80% excluded by the threshold, over 70% SMEs, 80% of goods from carbon-priced countries, HMRC costs). gov.uk/government/publications/introduction-of-carbon-border-adjustment-mechanism. Checked 12 July 2026.
- UN COMTRADE UK import values by sector, via Trading Economics and IndexBox aggregators (iron and steel, aluminium, fertiliser, cement, hydrogen). Latest available annual data. Checked 12 July 2026.
- UK STEEL / HMRC UK steel key statistics and HMRC trade data (EU share of steel imports, leading source countries). Checked 12 July 2026.
- MPA / INDEXBOX Mineral Products Association and IndexBox UK cement market data (import share of the UK market, main suppliers, Turkish growth). Checked 12 July 2026.
- AHDB Agriculture and Horticulture Development Board fertiliser import data (leading supplier countries and volumes). Checked 12 July 2026.
Trade-aggregator figures are secondary presentations of UN COMTRADE and are used for relative scale. Every gov.uk figure is primary. We reconfirm the pending items against gov.uk and legislation.gov.uk as the rules are laid.
See where you land
This feature is the big picture. The tool turns it into your position: whether the £50,000 threshold catches you, your exact registration and return dates, and an estimated cost with the method shown.