The CBAM cost of an import line is the number of certificates the importer must surrender, times the certificate price. The number of certificates follows from the goods' embedded emissions and the share of those emissions that CBAM charges in the year of import. Every input is published by the Commission.
The formula
For one import line:
emissions per tonne = default value × (1 + mark-up) or verified actual value
embedded emissions = tonnes × emissions per tonne
subject to CBAM = embedded emissions × CBAM factor
certificates = round up (subject to CBAM × (1 − carbon price deduction))
cost = certificates × certificate price
The 5 inputs and their sources:
| Input | Source | 2026 value |
|---|---|---|
| Default value | Annex I of Reg (EU) 2025/2621, corrected by Reg (EU) 2026/1740, by CN code and origin | per code |
| Mark-up | Same regulation | 10%, fertilisers 1% |
| CBAM factor | Article 31 of Reg (EU) 2023/956 | 2.5% |
| Carbon price deduction | Article 9, verified price paid in the country of origin | 0 unless proven |
| Certificate price | Commission, from EU ETS auctions | €75.36 Q1, €75.28 Q2 |
2 rules change results often. Indirect emissions count for cement and fertilisers only, so for steel and aluminium the default is the direct value. And certificates are whole units, so the count always rounds up.
Example 1: hot-rolled steel from India
1,000 tonnes of CN 7208 39 00, imported in Q2 2026, no supplier data.
| Step | Calculation | Result |
|---|---|---|
| Default value | India, heading 7208, route C | 4.28 tCO2e/t |
| With mark-up | 4.28 × 1.10 | 4.708 tCO2e/t |
| Embedded emissions | 1,000 × 4.708 | 4,708 tCO2e |
| Subject to CBAM | 4,708 × 2.5% | 117.7 tCO2e |
| Certificates | round up 117.7 | 118 |
| Cost | 118 × €75.28 | €8,883.04 |
Example 2: the same steel in later years
The default value is the same, but the mark-up and the factor are not. At a constant €75.28:
| Year | Emissions per tonne | Factor | Certificates | Cost |
|---|---|---|---|---|
| 2027 | 4.28 × 1.20 = 5.136 | 5% | 257 | €19,346.96 |
| 2028 | 4.28 × 1.30 = 5.564 | 10% | 557 | €41,930.96 |
| 2030 | 5.564 | 48.5% | 2,699 | €203,180.72 |
The factor continues to 61% in 2031, 73.5% in 2032, 86% in 2033 and 100% from 2034.
Example 3: aluminium slabs from China and India
500 tonnes of CN 7601 10 10, imported in 2026.
| China | India | |
|---|---|---|
| Default value, route K | 3.0 | 1.87 |
| With 10% mark-up | 3.3 | 2.057 |
| Embedded emissions | 1,650 tCO2e | 1,028.5 tCO2e |
| Subject to CBAM, 2.5% | 41.25 | 25.71 |
| Certificates | 42 | 26 |
| Cost at €75.28 | €3,161.76 | €1,957.28 |
The origin alone moves this line by 38%.
Example 4: fertiliser, where indirect emissions count
2,000 tonnes of CN 3102 10 12, urea in aqueous solution, from Egypt, 2026. Fertilisers include indirect emissions and carry a 1% mark-up.
| Step | Calculation | Result |
|---|---|---|
| Default value | direct 0.44 + indirect 0.02, published total | 0.46 tCO2e/t |
| With mark-up | 0.46 × 1.01 | 0.4646 tCO2e/t |
| Embedded emissions | 2,000 × 0.4646 | 929.2 tCO2e |
| Subject to CBAM | 929.2 × 2.5% | 23.23 tCO2e |
| Certificates | round up | 24 |
| Cost | 24 × €75.28 | €1,806.72 |
The same line from Russia uses a total of 0.49 and costs €1,882.
Example 5: a small line of fasteners
40 tonnes of CN 7318 15 95, screws and bolts, from China, 2026. The default for the heading is 6.375 tCO2e per tonne, 7.013 with the mark-up.
| Step | Result |
|---|---|
| Embedded emissions | 280.5 tCO2e |
| Subject to CBAM, 2.5% | 7.01 tCO2e |
| Certificates | 8 |
| Cost | €602.24 |
This line is below 50 tonnes. If the importer's total CBAM imports for the whole year also stay at or below 50 tonnes, the importer is exempt and pays nothing. If the year's total passes 50 tonnes, this line is charged like any other. The threshold counts the importer's whole year: see the 50-tonne threshold.
Mistakes that change the answer
- Looking up the default at the wrong code length. Most defaults are published at a four- or 6-digit heading. An 8-digit code takes the most specific row that covers it. After the 31 July 2026 correction, many rows moved between code lengths.
- Adding indirect emissions for steel or aluminium. They count only for cement and fertilisers.
- Forgetting the mark-up, or applying it to verified actual data, where it does not apply.
- Charging the full emissions. In 2026 the CBAM factor charges 2.5% of them.
- Using the wrong quarter's price. Each 2026 quarter has its own price, applied to goods imported in that quarter.
- Treating a small shipment as exempt. The 50 t threshold is per importer per calendar year.
Check your own lines
The CBAM calculator runs this formula for any CN code, origin, tonnage and year, and shows each step with its article. To run it on every import line inside an ERP or customs system, the same calculation is one call to /v1/resolve in the CBAM API.
Sources: Regulation (EU) 2023/956, Articles 7, 9 and 31, as amended by Regulation (EU) 2025/2083. Default values from Regulation (EU) 2026/1740. Prices from the Commission's price page. All examples computed on 16 September 2026 with the CBAM Data engine.