Ship Carbon Intensity Indicator (CII) Calculator.
Calculate your vessel's operational CII rating, evaluate mandatory 2023–2030 reduction trajectories, model slow-steaming sensitivity, and export executive compliance reports.
Vessel & Voyage Parameters
MARPOL Annex VI · MEPC.354(78)
Awaiting Vessel Data
Enter capacity, distance sailed, and fuel burned to instantly calculate the attained CII, required baseline, and operational grade.
About the CII Calculator
This interactive tool lets shipowners and operators evaluate their vessel's operational energy efficiency based on the International Maritime Organization (IMO) MARPOL Annex VI regulations. By inputting details about sea conditions, operational speed, draft, and fuel consumption, you can simulate and optimize your annual operational Carbon Intensity Indicator (CII).
How CII is Calculated
The attained CII represents the carbon emissions of the ship per cargo capacity (usually Deadweight Tonnage, DWT) and nautical mile. This calculator uses the annual fuel consumption, distance sailed, and vessel capacity to determine the attained and required CII ratings in accordance with the IMO G1-G4 guidelines.
Compliance Requirements
Ships are rated from A (major superior) to E (inferior). A rating of C or better is required. Vessels receiving a D rating for three consecutive years, or an E rating in a single year, must develop a corrective action plan as part of their Ship Energy Efficiency Management Plan (SEEMP) Part III.
Frequently Asked Questions
What is EEXI and EEDI?
EEDI (Energy Efficiency Design Index) is a design standard for new ships built after 2013, requiring a minimum energy efficiency level per capacity-mile.
EEXI (Energy Efficiency Existing Ship Index) is the design standard for existing ships (built before 2013 or not subject to EEDI). Both indexes calculate the theoretical design efficiency based on installed power, speed, capacity, and fuel factors.
What is EEXI in shipping?
EEXI (Energy Efficiency Existing Ship Index) is a one-time technical measure introduced by the IMO under MARPOL Annex VI to evaluate the design energy efficiency of existing ships over 400 GT. It requires existing vessels to meet a specific baseline efficiency comparable to newer EEDI-compliant vessels.
What is the difference between EEXI and CII?
EEXI is a design/technical index calculated once. It measures how the ship is built (its theoretical efficiency).
CII (Carbon Intensity Indicator) is an operational measure calculated annually based on actual fuel consumed and distance sailed. It measures how the ship is operated in practice.
How to calculate EEXI for ships?
EEXI is calculated by dividing the CO₂ emissions from the vessel's propulsion and auxiliary systems by the product of the ship's capacity (DWT or GT) and its reference speed:
EEXI = (CO₂ Emissions from Main + Aux Engines) / (Capacity × Reference Speed)
This represents the theoretical grams of CO₂ emitted per capacity-mile under reference load conditions.
What is the difference between EEOI and EEDI?
EEDI (Energy Efficiency Design Index) is a design index for new ships (theoretical efficiency under standard conditions).
EEOI (Energy Efficiency Operational Indicator) is an operational monitoring tool that measures actual CO₂ emissions per actual cargo carried per nautical mile during real voyages. EEOI uses actual cargo weight, whereas EEDI (and CII) uses maximum ship capacity (DWT/GT).
What is the carbon intensity indicator?
The Carbon Intensity Indicator (CII) is an operational rating system introduced by the IMO under MARPOL Annex VI. It rates ships (5,000 GT and above) annually on a scale from A (major superior) to E (inferior) based on their actual operational carbon emissions per transport capacity and distance.
How do you measure carbon intensity?
Operational carbon intensity is measured by dividing the ship's annual CO₂ emissions (calculated from actual fuel consumed multiplied by fuel-specific conversion factors) by its annual transport work (vessel capacity in DWT or GT multiplied by total distance sailed in nautical miles).
What is a good CI score?
Under the IMO CII framework, a "good" rating is an A or B rating (major or minor superior energy efficiency performance). A rating of C is acceptable (moderate). Ratings of D (for three consecutive years) or E require corrective action plans in the vessel's SEEMP.
What are the 4 pillars of CII?
The management and compliance of a ship's Carbon Intensity Indicator (CII) are structured around the 4 pillars of the SEEMP (Ship Energy Efficiency Management Plan):
1. Planning: Establishing baselines, target CII ratings, and detailed operational measures to meet target guidelines.
2. Implementation / Operation: Putting planned actions (e.g., speed optimization, route planning, trim optimization) into daily practice.
3. Monitoring & Reporting: Collecting daily fuel consumption and voyage data under the IMO Data Collection System (DCS).
4. Self-Evaluation & Corrective Action: Auditing annual results and developing corrective plans if the vessel falls below a 'C' rating.