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CII – Carbon Intensity Indicator

The CII in a nutshell

The CII (Carbon Intensity Indicator) is a measure for a ship’s energy efficiency and is given in grams of CO2 emitted per cargo-carrying capacity and nautical mile. 

The first year of the attained annual operational CII verification will be 2024 for the operation in calendar year 2023. Vessels, based on their performance, will receive an environmental rating of A (major superior), B (minor superior), C (moderate), D (minor inferior) or E (inferior performance level). The rating thresholds will become increasingly stringent towards 2030. 



Connection between the CII, DCS and SEEMP Part III


Starting in 2024, the CII must be calculated and reported to the Data Collection System (DCS) verifier together with the aggregated DCS data for the previous year, including any correction factors and voyage adjustments. Deadline for DCS and CII submission remains unchanged - no later than 31 March each year.

The attained annual operational CII and the environmental rating (A to E) will be noted on the DCS Statement of Compliance (SoC), which will be required to be kept on board for five years. 

In case of a D rating for three consecutive years or one E rating, the SEEMP Part III must be updated with a corrective action plan and verified before the SoC can be issued. The corrective action plan should consist of an analysis of why the required CII was not achieved and include a revised implementation plan. 

Calculation of the CII

The CII unit is “grams of CO2 emitted per cargo-carrying capacity and nautical mile”, whereby cargo capacity is either deadweight or gross tonnage depending on ship type. In addition, to cater for special design and operational circumstances, the correction factors and voyage adjustments can be applied to the basic CII calculations for the purposes of determining the rating.

Simplified attained annual CII formula:


More detailed information about Correction factors can be found at Corrected CII.

How DNV can help you with the CII

CII – Class services

As a DCS customer, your vessels’ CII including correction factors and voyage adjustments will be automatically calculated based on uploaded DCS data. You also have access to the Emissions Insights dashboard on the Veracity platform, where you can monitor the preliminary CII rating of each of your ships and entire fleet. This enables you to evaluate and improve your fleet performance throughout the year to be sure you meet your CII targets in the upcoming years. In case of inferior CII rating, SEEMP Part III Corrective Actions Plan can be prepared using our SEEMP Part III generator.

CII – Advisory services

Our advisory experts help you to develop decarbonization strategies and reduction plans. With our solutions, you can navigate the many options and ensure compliance with IMO requirements and those of other stakeholders. 

Related links


EEXI and CII requirements taking effect from 1 January 2023

Read the update from 17 January 2023


New DCS reporting scheme for CII correction factors and out-of-scope activities for MRV

Read our news from 19 September 2022



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