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How the calculator actually calculates

The free calculator is deliberately simple. Here's every step, with sources. If the math looks wrong for your situation, trust your gut — this is triage, not a binding filing.

The formula

For each import line:

certificate_cost_EUR
  = annual_tonnes
  × (direct_embedded_emissions + indirect_embedded_emissions)
  × current_ETS_price_EUR_per_tonne_CO2
  

Units cancel cleanly: tonnes of product × (tonnes CO₂ per tonne of product) × EUR/tonne CO₂ = EUR.

Default emissions factors

When you use the free calculator (or before your supplier portal is populated), we use the EU default values from Implementing Regulation (EU) 2023/1773. These are deliberately high — the EU wants to nudge importers toward collecting actual supplier data.

Aluminium's huge indirect factor reflects the electricity needed for smelting. Hydrogen's 9.0 reflects the carbon cost of grey hydrogen production; green hydrogen from your supplier would score much lower.

ETS price source

The EU Emissions Trading System auction price is what CBAM certificates will cost. We pull this from:

1. EEX (European Energy Exchange) daily settlement — published at eex.com/en/market-data/emission-allowances/. Free, public.
2. If EEX is unreachable, we fall back to a constant from an environment variable (currently €85/tonne).
3. Manual override — occasional, when markets are volatile and we want to use a conservative figure.

The calculator shows you which source we used, with an "as of" date. Check /api/ets-price for the live number.

Worked example — 500 tonnes of hot-rolled steel from Turkey

You import 500 tonnes of CN code 72081000 (flat-rolled products of iron or non-alloy steel, hot-rolled, in coils) from a Turkish supplier. Current ETS price: €85/tonne CO₂.

Step 1 — classify the CN code. 72081000 is in the iron-and-steel sector under CBAM Annex I. In scope.

Step 2 — embedded emissions per tonne. Iron-and-steel default: 1.880 direct + 0.275 indirect = 2.155 t CO₂ per tonne of steel.

Step 3 — total embedded emissions. 500 × 2.155 = 1,077.5 t CO₂.

Step 4 — certificate cost. 1,077.5 × €85 = €91,587.50 per year.

Step 5 — scenarios. If ETS drops 30% (to €59.50/tonne): €64,111. If it rises 40% (to €119/tonne): €128,223. The calculator shows all three.

Important caveats — read these

• Default factors are conservative. Your Turkish supplier's actual mill might produce steel at 1.4 t CO₂/tonne (well below the 2.155 default) — say, if they use electric arc furnace instead of blast furnace. Starter tier collects that data and gives you a real number.
• Carbon price already paid in origin country is deductible. If the supplier's country has a carbon tax (e.g. UK ETS, Turkey's planned scheme) and the supplier can evidence payment, you deduct that from your CBAM obligation. The free calculator ignores this — Starter tier captures and applies the deduction.
• The calculator uses annual average ETS price. CBAM certificates are actually priced at the weekly average from 2027 onwards, quarterly for 2026. Your real cost will drift around our estimate.
• We don't cover downstream products yet. CBAM Annex I recently added certain processed goods (screws, bolts, some tubes). If your CN code is on the edge, email us — we'll tell you if it's in our seed table.

Sources

• Regulation (EU) 2023/956 — the CBAM Regulation itself. EUR-Lex.
• Implementing Regulation (EU) 2023/1773 — embedded emissions methodology + default values. EUR-Lex.
• European Commission CBAM Q&A page — quarterly updated guidance.
• EEX EUA auction results — daily EU ETS clearing prices.

Not legal advice. The calculator is informational. For a binding CBAM declaration you need supplier-specific emissions data, an accredited verifier, and often a customs/trade lawyer.