CII for gas carriers: required CII, rating boundaries and calculator
The carbon intensity a gas carrier must reach each year from 2023 to 2030, by size, with the IMO reference line and the A to E boundaries. Try it on your own ship below.
Updated 2026-10-20
Calculate
Required CII for gas carriers, 2023 to 2030
| Size | 2023 | 2024 | 2025 | 2026 | 2027 | 2028 | 2029 | 2030 |
|---|---|---|---|---|---|---|---|---|
| 5,000 dwt | 33.33 | 32.62 | 31.92 | 31.22 | 30.30 | 29.38 | 28.46 | 27.54 |
| 25,000 dwt | 11.92 | 11.67 | 11.41 | 11.16 | 10.83 | 10.51 | 10.18 | 9.85 |
| 55,000 dwt | 7.20 | 7.05 | 6.90 | 6.75 | 6.55 | 6.35 | 6.15 | 5.95 |
| 85,000 dwt | 8.46 | 8.28 | 8.10 | 7.93 | 7.69 | 7.46 | 7.23 | 6.99 |
g CO₂ per dwt-nautical mile. Required CII = (1 − Z/100) × a × capacity−c, with Z from 5% in 2023 to 21.5% in 2030 (resolution MEPC.338(76) as amended).
The reference line
From 65,000 dwt a different reference line (a = 144,050,000,000, c = 2.071) and different rating boundaries apply. Capacity basis: deadweight (G2, resolution MEPC.353(78)).
Rating boundaries in 2026
| Size | A up to | B up to | C up to | D up to | E |
|---|---|---|---|---|---|
| 5,000 dwt | 26.54 | 29.66 | 33.09 | 39.03 | above |
| 25,000 dwt | 9.49 | 10.61 | 11.83 | 13.95 | above |
| 55,000 dwt | 5.73 | 6.41 | 7.15 | 8.43 | above |
| 85,000 dwt | 6.42 | 7.21 | 8.88 | 11.41 | above |
Boundaries are the required CII multiplied by 0.85, 0.95, 1.06, 1.25 (G4, resolution MEPC.354(78)).
Rated D or E?
A ship rated D three years running, or E once, needs a corrective action plan in its SEEMP Part III. How the plan is prepared, or check what EU ETS and FuelEU cost the same ship in the EU ETS and FuelEU calculators.
Questions
What is the required CII for a 55,000 dwt gas carrier in 2027?
6.55 g CO₂ per dwt-nautical mile: the reference value of 7.58 reduced by 13.625%.
Which capacity is used for the CII of a gas carrier?
Deadweight. From 65,000 dwt a different reference line (a = 144,050,000,000, c = 2.071) and different rating boundaries apply.
What are the CII rating boundaries for gas carriers?
The required CII multiplied by 0.85, 0.95, 1.06 and 1.25. For a 55,000 dwt ship in 2026 a CII up to 5.73 is A, up to 6.41 B, up to 7.15 C, up to 8.43 D, and above that E.
How many gas carriers report to the EU MRV register?
418 in the reporting period 2025, with a median of 5,051 tonnes of CO₂ each.
EU ETS, FuelEU, CII and UK ETS for each ship, from the public register or your own data.