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How to fill the CBAM Communication Template
Your EU customer asked for "the CBAM template". They mean one specific Excel file published by the European Commission. Here is what each sheet wants, and where producers get stuck.
Fill it automatically for steel or aluminium →
What the file is
The CBAM Communication Template for Installations is the Commission's standard way for a non-EU producer to hand emissions data to an EU importer. Using it is not legally mandatory — the importer needs the numbers, not the format — but every importer asks for it, because their own reporting is built around it. It is a protected Excel workbook of roughly 19 sheets; you fill in five of them and the rest calculate themselves.
The five sheets you actually fill
- A_InstData — who and where you are: installation name, address, country, UN/LOCODE, the reporting year, and a list of your production processes and the goods they make.
- B_EmInst — every source of emissions at the installation: fuels burned, carbonates such as limestone, electrodes, and carbon entering or leaving in a mass balance.
- C_Emissions&Energy — the totals, plus how good your data is and how it was checked.
- D_Processes — one block per production process: how much you made, how much went to customers, how much you consumed yourself, and the emissions attributed to it.
- E_PurchPrec — steel or aluminium you bought and fed into the process, with its own emissions value per tonne.
Five mistakes that get the file sent back
- Using your fiscal year. The definitive period requires a calendar year, 1 January to 31 December.
- Reporting the company, not the site. One installation is one physical site. Two factories mean two files.
- Counting the steel you bought as free. Purchased steel or aluminium carries its supplier's emissions into your product. For a fabricator this is usually most of the total.
- Entering the mass in the product instead of the mass consumed. If 100 tonnes of rod go in and 80 tonnes of screws come out, the figure is 100 — offcuts included.
- Adding electricity to the total. For iron, steel and aluminium the definitive period counts direct emissions only. The template asks for electricity, but it does not enter the product's value.
The part most people get wrong: supplier values
You may use a number your supplier gave you only if it comes with a verification report from an accredited verifier covering the year the material was produced. An email or a datasheet is not enough. Without that report, the country default value applies to that material, plus a mark-up of 10% in 2026, 20% in 2027 and 30% from 2028 — which is usually far worse than reality.
Filling it automatically
For iron, steel and aluminium, this site does it for you: enter production, fuels and purchased material, and download the official template with your numbers in the right cells, plus a report that shows your customer what they save. Everything runs in your browser — the data never reaches us. The calculation is verified against the Commission's own worked examples.
Where to get the file yourself
The template, the filled sector examples and the ten guidance documents of 14 August 2026 are all free from the European Commission. If you would rather upload once and share with every customer, the Commission also runs a free operator portal (O3CI) — it needs an EU Login account and its manual runs to 146 pages, but it is the official route and costs nothing.
CBAM File is a free browser-based calculator for non-EU steel and aluminium producers. Your production data never leaves your browser. Open the calculator →
Default values by country · Communication Template · Got a data request? · Steel · Aluminium