Before you start: what records do you have?
You need figures for one full year, the same year for production and fuel. Typical sources:
- Production: sales ledger, dispatch notes, production or stock log (tonnes made, not tonnes sold).
- Fuel: supplier invoices, delivery notes, gas or electricity style meter readings. Accounting software usually holds only spend, so check the invoice for litres, m3 or kWh.
- Process data: plant or laboratory records (clinker ratio, anode use, furnace logs). Often held by an engineer rather than in a system.
Only have spend? Use the helper under section 2. The answer will be rough, so treat it as a guide to which side of the default you may fall on. Data checklist (PDF)
1. Your product
This does not change your emissions estimate. It shows whether the country has a carbon pricing scheme that HMRC currently recognises for Carbon Price Relief.
Use the production of the plant or line that makes the product, and enter its fuel and process data for the same year. If the plant makes several products, the emissions need allocating between them first.
2. Fuels burned on site
Only have spend? Convert it to a quantity
Enter both figures. Quantity = spend divided by price per unit. Use the price for the unit on the invoice (per litre, per tonne, per kWh), then type the result into the matching fuel row below in that same unit.
Prices move through the year, so this is approximate. Do not use a spend based figure in a CBAM return.
Enter annual quantities for the same year as your production. Fuel invoices, delivery notes and meter readings are the usual sources. Pick the unit your records use. Include fuel used as a feedstock (for example natural gas in ammonia or hydrogen). Leave blank if unused.
Other direct CO2 you have already calculatedtonnes CO2 per year
3. Process emissions and adjustments
Examples: bought-in pig iron, DRI or billets for a steel product, clinker for cement, ammonia for a fertiliser.
Your result
Enter your production volume and at least one fuel or process input to see a result.
0Your estimate, tCO2e per tonne
0UK default value, tCO2e per tonne
UK default
Your estimate
This is a screening estimate. HMRC will not accept it as it stands: actual emissions must be calculated to the UK monitoring rules and independently verified before they can replace the default.
Where it comes from
Illustrative cost effect
Carbon price relief
Select a country in section 1 to see whether it has a scheme HMRC currently recognises.
Want a follow up?
Optional. Leave your details and we will follow up on this result and tell you what a proper calculation would involve. We send only the sector, country if you chose one, code and the two intensity figures, not your production volume.
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- UK CBAM counts direct emissions only at launch. Indirect emissions such as purchased electricity are delayed until 2029 at the earliest.
- Actual emissions used in place of a default have to be verified by an independent, accredited verifier. Driftwatch does not verify.
- A return filed on default values cannot be amended later with actual data, so get your numbers before the first return.
Want this done properly?
We calculate embedded emissions from your production data and prepare the evidence pack for an independent verifier.
Book a discovery call
Method and sources. Fuel emissions use IPCC 2006 Guidelines default emission factors and net calorific values. Cement calcination uses the IPCC Tier 1 clinker factor of 0.52 tCO2 per tonne, corrected for kiln dust. Carbon in anodes, electrodes and flux is converted to CO2 by mass (44/12). Fluorinated gases and nitrous oxide use AR5 100 year global warming potentials (CF4 6,630, C2F6 11,100, N2O 265). Default values are from the official GOV.UK pages published on 16 October 2026 and were in a draft notice at the time of writing. The illustrative sector rates (iron and steel 9.69, aluminium 9.79, cement 8.78, fertiliser 1.45, hydrogen 9.24 pounds per tonne of CO2e) are not binding, and binding rates are set quarterly. This tool does not apply the UK monitoring, reporting and verification rules, biogenic carbon rules or allocation rules, so treat the result as a screening estimate. Check the current position on GOV.UK before relying on any figure.