UK carbon border tax (CBAM) starts on 1 January 2027
Find out if the carbon border tax applies to your imports, and what it will cost
From 1 January 2027, UK businesses that import steel, aluminium, cement, fertiliser or hydrogen pay tax on the carbon in those goods once their imports reach £50,000 in 12 months. Load your import entries and CBAM Checker shows whether you're liable, when to register and roughly what you'll pay.
Free to use. No account. Your file stays on your computer.
The dates that matter
- 1 Jan 2027CBAM starts. Imports from this date count towards the £50,000.
- 1 Jan 2028HMRC's registration service opens.
- 31 Jan 2028Register if you reached £50,000 during 2027.
- 31 May 2028First return and payment due, for 2027.
How it works
Load your import entries
A CSV from your customs broker or your own system. Your file's column names are fine: you match them on the page.
See where you stand
Which lines count, the date you reach £50,000 under HMRC's two tests, your registration deadline and an estimate of the tax.
Stay on top of it
Download a records file for HMRC, save the check, and get a reminder on the 1st of each month to check again.
What it checks
- Which goods count. Every commodity code against HMRC's lists for the five sectors, including exclusions such as steel scrap.
- The £50,000 threshold. HMRC's look-back test on the 1st of each month, and the forward test for the next 30 days.
- Roughly what you'll pay. HMRC's default carbon values for each product, or your supplier's verified figures.
- Where you can pay less. Relief for carbon tax already paid abroad, and whether paying a verifier is worth it for each supplier.
Your import data stays with you
The checker runs in your browser. Your file isn't uploaded: the site's security settings stop the page sending data anywhere. There's no account to create.
Pricing
Use the checker free. When you want help, we can check your position or do the work for you.
Checker
Free
- As many checks as you like
- Threshold, deadlines and tax estimate
- Records file and monthly reminders
Readiness check
From £500 one-off
- We review your imports and suppliers
- Whether and when you must register
- A plan: what to get from which supplier
Done for you
From £1,500 a year
- Help registering with HMRC
- We prepare your CBAM returns
- We chase suppliers for emissions data and carbon price forms
- Monthly threshold checks
Paid work is covered by a written quote and our terms of use.
For customs brokers
Your clients will ask you about CBAM first, because you hold their entry data. Check every client free, then choose how much you want to do.
Questions
How do I know if my goods are covered?
Type the commodity code into our free code lookup. It shows whether CBAM applies, the sector, any exclusion, HMRC's default emissions value and roughly the tax per tonne. To check every import at once, load your file into the checker.
What file do I need?
One row per customs entry line, with the date, commodity code, customs value in pounds and net mass in kg. A CSV export from your broker or system usually has all four. For Excel files, save the sheet as CSV first.
Is it tax advice?
No. It's an estimate based on HMRC's published rules and data. Check the results against HMRC's guidance, or ask us for a readiness check. You stay responsible for your own registration, returns and payments: see our terms of use.
Does it file my return?
No. Returns go through HMRC's CBAM service. Our done-for-you service prepares them for you.
Which rates does it use?
HMRC's illustrative rates published on 16 October 2026, until HMRC publishes the binding rate for each quarter. You can change the rates in the checker's settings.
Does it cover the EU's CBAM?
No, only the UK's. The EU has its own CBAM with different rules and dates.
Get in touch
Ask a question, book a 15-minute call, or tell us about your clients. We reply by email.