What must my installation report to its EU customers?

Since 1 January 2026, EU importers of cement, electricity, fertilisers, iron and steel, aluminium and hydrogen pay for the embedded emissions of those goods by buying and surrendering CBAM certificates. Without data from the producer, they must use the default values set by the Commission, which carry a mark-up of 10 % in 2026, 20 % in 2027 and 30 % from 2028. With verified actual emissions from your installation, they pay on your real figures, without mark-up.

Your customers submit their first CBAM declaration, for 2026 imports, by 30 September 2027. The actual emissions they use must be verified by an accredited verifier. The figures they need from you are two per product: the specific embedded emissions and the specific embedded free allocation.

You describe the installation and the reporting period, the production processes and the goods they make, the source streams, electricity, heat and precursors. The calculator follows the order of the regulation in nine steps and returns, for each product:

• the specific embedded emissions, direct and indirect, per functional unit and per tonne;
• the specific embedded free allocation, with and without the CBAM factor and the cross-sectoral correction factor;
• the share of the result that rests on default values;
• the items that alone exceed the 5 % materiality threshold, which the verifier will look at, and the evidence to prepare;
• an operator's report with the items of Annex IV, point 1.1, of Implementing Regulation (EU) 2025/2547, in the language you choose for your customer;
• a supplier data file that your EU customers load into the CBAM Importer Calculator.

It covers every sector of Annex I of the CBAM Regulation: cement, electricity, fertilisers, iron and steel, aluminium and hydrogen, with their functional units (tonnes, tonnes of clinker, kg of nitrogen, MWh). Every choice is written in an interpretation log with its source.

Emissions of the installation. Source streams by the calculation-based methodology: combustion (Equations 5, 6 and 10), process emissions (Equation 11) and mass balance (Equations 12 and 15). The standard factors of Annex II, point G, are proposed and can be changed. Continuously measured sources follow the measurement-based methodology of Annex II, section B.6 (Equations 16 to 19), with the 80 % data availability rule and a corroborating calculation. CO2 transferred to capture, geological storage or permanent chemical bonding is deducted only when every condition of Annex II, section B.8, is proven, and only for the proven share.

Heat and waste gases. Measurable heat is calculated with the three methods of Annex II, section C.1, and its emission factor with Annex III, section A.2.2, including cogeneration with the harmonised reference efficiencies of Annex III, section C. Waste gases follow Equations 53 and 54.

Attribution and embedded emissions. Emissions are attributed to production processes (Equations 55 and 56), then divided by the activity level: simple goods with Equations 57 and 58, complex goods with Equations 59 to 63, adding the embedded emissions of precursors. Supplier data for purchased precursors are used only if verified; otherwise the default value with the mark-up of the precursor's year.

Free allocation. The CBAM benchmark, column A, for the production route of the installation, chained through the precursors (Implementing Regulation (EU) 2025/2620, Equations 2 to 5), and reported both without and with the CBAM factor and cross-sectoral correction factor of the year. The SEFA of electricity is zero.

Indirect emissions come from the electricity your processes consume, multiplied by an emission factor. The calculator does not ship a table of grid factors: you enter the factor yourself, from one of two sources.

1. The default grid factor of your country, from Annex II of Commission Implementing Regulation (EU) 2025/2621 (EUR-Lex). Find your country in the table and enter the value in tCO2e/MWh.
2. An actual emission factor, where Implementing Regulation (EU) 2025/2547 allows one and you can document it, for example electricity from a power purchase agreement.

If the electricity comes from several sources, enter each with its own factor: the calculator takes the weighted average (Article 9). If you enter no factor, the indirect emissions from electricity are shown as not evaluated, never as zero.

The calculator reproduces the examples of the Commission's guidance documents. Two of them:

Hydrogen by steam reforming, reporting year 2028 (guidance document 5b). An installation burns 190,000 t of natural gas (net calorific value 48 GJ/t, emission factor 56.1 tCO2/TJ), exports 800 TJ of measurable heat and produces 55,000 t of hydrogen (CN 2804 10 00).

Steel rails, reporting year 2027 (guidance document 5d, example E1). The free allocation is chained through the precursors: sinter (0.086) into pig iron (benchmark 1.089, 1.4 t of sinter per t) gives 1.2094; crude steel (benchmark 0.188, 0.8 t of pig iron per t); rails (benchmark 0.057, 1.042 t of crude steel per t).

The supplier file carries both values. The importer's calculator uses the value with factors for the certificates; if only the value without factors is present, it applies the factors of the year and says so.

Where a figure printed in the Commission guidance does not follow from the guidance's own inputs, the calculator uses the recalculated value and says so in the interpretation log. Two examples from guidance document 5d:

The calculator also flags numbering errors in Implementing Regulation (EU) 2025/2547 itself: Annex III uses "Equation 52" twice, and point A.2.2 places the reference efficiencies in Annex II, point G, while they are in Annex III, section C.

The calculator runs entirely in your browser. Its Content Security Policy blocks every network connection (connect-src 'none'): nothing is uploaded and Seetalabs® stores nothing. To keep your inputs, save them as a file on your computer. You decide what to send to your customers, and when.

The page is in English. The calculator works in 14 languages; you can also write the operator's report in a different language from the one you work in, to match your customer's.

English · Italiano · Deutsch · Français · Español · Polski · Nederlands · Português · Türkçe · 中文 · العربية · Українська · 한국어 · Tiếng Việt

The eight EU languages use the terms of the official language versions of the regulations. Arabic, Ukrainian, Korean and Vietnamese show the English regulatory term in brackets.

• Regulation (EU) 2023/956 (CBAM Regulation), as amended by Regulation (EU) 2025/2083.
• Implementing Regulation (EU) 2025/2547: monitoring and calculation of embedded emissions (Annex II point G standard factors; Annex III heat and reference efficiencies; Annex IV operator's report).
• Implementing Regulation (EU) 2025/2546: verification (materiality threshold, Article 5(1)).
• Implementing Regulation (EU) 2025/2620: CBAM benchmarks and free allocation.
• Implementing Regulation (EU) 2025/2621, corrected by Implementing Regulation (EU) 2026/1740: default values and, in Annex II, default grid emission factors.
• Commission guidance documents on embedded emissions (worked examples 5a, 5b, 5d; guidance 3 for heat).

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