Is my business in scope of the UK CBAM? The £50,000 threshold explained
You must register for the UK CBAM once the value of the CBAM goods you import meets or exceeds £50,000. That £50,000 is not a simple annual figure. It is a rolling test with two limbs, both measured on the value of the goods, and either one can catch you: a 30-day forward look on any given day, and a 12-month backward look taken on the first of each month.
What is measured: the value of the goods
The threshold is measured on the value of the CBAM goods you import, in practice their customs value, not on their embodied emissions and not on the CBAM charge itself. So the test to watch is a commercial one you already track: how much are you spending to bring in steel, aluminium, cement, fertiliser or hydrogen goods. If the value of those specific goods reaches £50,000, the registration obligation is triggered even before you have worked out a single tonne of emissions.
The two limbs, in plain terms
The rolling test has two separate triggers. You are liable to register if either is met.
- The 30-day forward look (any day). On any given day, consider whether you expect the total value of CBAM goods you will import over the next 30 days to reach £50,000. If it does, that day triggers liability. This limb is about what is coming, not what has already landed.
- The 12-month backward look (first of the month). On the first day of each month, look back over the preceding 12 months and check whether the total value of CBAM goods you imported reached £50,000. If it did, you are liable.
The practical upshot is that a steady importer will usually be caught by the backward look once their running 12-month total crosses £50,000, while an occasional importer can be caught by the forward look the moment a single large order is on the horizon.
Two worked examples
The steady importer. A fabricator brings in roughly £6,000 of steel sections every month. No single month is large, but by the fifth or sixth month the running 12-month total passes £50,000. On the first of the month after it crosses, the backward look catches them and they become liable to register.
The occasional importer. A contractor imports almost nothing most of the year, then places one order for £70,000 of aluminium extrusions arriving over the next three weeks. Their annual total might still look modest, but on the day they expect that consignment the 30-day forward look is met, and they are liable from that day. This is why a low yearly total is not a safe assumption.
Borderline is a live risk, not a comfort. If your CBAM imports sit near £50,000, treat the threshold as something to monitor monthly, not a line you are safely under. A single large consignment can move you from out to in on one day through the forward look.
What being in scope means
Once either limb is met you are the liable person for CBAM: you register with HMRC, keep the records, file returns and pay the charge. There is a year-one easement giving businesses until 31 January 2028 to register (otherwise the deadline is within 30 days of becoming liable), the first accounting period runs 1 January to 31 December 2027, and the first return and payment are due 31 May 2028. Our key dates guide sets out the full timeline.
How to check your position
Run your rough annual value of CBAM goods through the free scope check: it tests it against £50,000 and flags a borderline zone just below the line. For a dated, personalised answer with your exact registration and return dates and an estimated cost, the paid report applies the test to your specific figures.
Frequently asked questions
Is the £50,000 threshold based on value or emissions?
On value. It is measured on the customs value of the CBAM goods you import, not on their embodied emissions or on the CBAM charge.
What are the two limbs of the test?
A 30-day forward look (on any day, whether 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 (whether you imported £50,000 or more over the preceding 12 months). Either one triggers liability.
Can one large order put me in scope even if my yearly total is low?
Yes. The forward look means a single large expected consignment can trip you into scope on any given day, even if your annual total would otherwise stay under the threshold.
Sources
- GOV.UK, Introduction of the Carbon Border Adjustment Mechanism, on the £50,000 threshold measured on the value of goods. gov.uk
- GOV.UK, CBAM Policy Summary, on the two-limbed rolling test (30-day forward look and 12-month backward look) and the registration timing. gov.uk
Content current as of 12 July 2026. The threshold basis is confirmed; some operative detail sits in secondary legislation being finalised in 2026. Re-check the primary source before acting on anything time-sensitive.
Not sure which side of £50,000 you are on?
Run the free scope check, or get a dated, personalised report with your exact registration and return dates and an estimated cost.
Check my CBAM scope → get my report