CII calculators by ship type

CII rating calculator for a container ship

The IMO's carbon intensity rating compares a container ship's attained CII with a required line for its size. For a container ship, the reference line is 1984 × capacity^−0.489, reduced each year by the published factor: 11% for 2026 and 13.625% for 2027, rising to 21.5% in 2030 (MEPC.400(83)).

The rating boundaries for a container ship

A rating of A applies when the attained figure is at or below 0.83 times the required figure; B up to 0.94; C up to 1.07; D up to 1.19; and E above that.

What moves your rating

• Speed and routing, which change fuel burned per mile.
• Hull and propeller condition.
• Fuel type, through its CO2 conversion factor.
• Distance sailed in ballast, which adds CO2 without adding cargo.

The calculator below is preset for a container ship. Change the fuel and distance to match a year of your own ship and switch the year to see the effect of the tightening factor. Voyage adjustments and correction factors are not applied.