CII Checker
IMO Carbon Intensity Indicator rating calculator
Carbon Intensity IndicatorCII Checker
Calculate and assess your vessel's CII rating in compliance with IMO MEPC regulations. Track carbon intensity performance against international standards and plan your decarbonization strategy.
CII Rating
E
Inferior
Annual CO2
43.6kt
160.0k trees to offset
Compliance
Non-Compliant
7% reduction target (2024)
CII Value
17.4
vs 9.3 required
Cargo ships that carry all of their load in containers for efficient handling
Range: 10,000 - 250,000
Current Rating
CII Value
17.44
gCO2/dwt-nmile
Required CII
9.25
(7% reduction)
Non-Compliant - Immediate Action
Submit corrective action plan to flag administration
The Carbon Intensity Indicator (CII) represents a groundbreaking regulatory mechanism introduced by the International Maritime Organization (IMO) to measure and improve the carbon efficiency of ships. As part of the IMO's broader strategy to reduce greenhouse gas emissions from international shipping, the CII framework came into effect on January 1, 2023, making it one of the most significant environmental regulations in maritime history.
The CII is expressed as grams of CO2 emitted per cargo-carrying capacity and nautical mile traveled. For most ship types, this translates to grams of CO2 per deadweight ton-nautical mile (gCO2/dwt-nm), while passenger ships use gross tonnage instead. This metric captures the essential relationship between cargo transported, distance covered, and emissions generated, providing a comprehensive view of a ship's operational efficiency.
What makes CII particularly significant is its universal applicability. All ships of 5,000 gross tonnage and above engaged in international voyages must calculate and report their CII, covering bulk carriers, gas carriers, tankers, container ships, general cargo ships, refrigerated cargo carriers, combination carriers, LNG carriers, and Ro-Ro vessels. This broad scope ensures that the regulation affects a substantial portion of the global fleet.
The rating system assigns a grade from A to E based on how the ship's attained CII compares to the required annual operational CII. A rating of A or B indicates superior or good performance, while C represents moderate performance meeting the minimum requirements. Ratings D and E trigger compliance requirements, including the development of corrective action plans. This graduated approach provides both recognition for good performers and a clear pathway for improvement for underperformers.
The maritime industry is responsible for approximately 3% of global CO2 emissions, and the CII regulation represents a critical step toward decarbonization. By establishing clear performance metrics and consequences for non-compliance, the IMO has created a powerful incentive for ship operators to invest in efficiency improvements. The regulation also supports broader industry efforts to meet climate commitments under the Paris Agreement and positions shipping as a responsible contributor to global climate goals.
Total Annual CO2
43.60 kt
Equivalent Trees for Offset
159,997.32
Based on 1 tree absorbing ~21 kg CO2/year
Emissions per Nautical Mile
0.87 kg
| Ship Type | Coefficient a | Coefficient c | Reference Line* | Capacity Range |
|---|---|---|---|---|
| Bulk Carrier | 4,745 | 0.6225 | 5.64 | 10,000 - 350,000 DWT |
| Gas Carrier | 10,093 | 0.6310 | 10.94 | 2,000 - 80,000 DWT |
| Tanker | 5,247 | 0.6105 | 7.10 | 4,000 - 300,000 DWT |
| Container Ship | 1,984 | 0.4894 | 9.95 | 10,000 - 250,000 DWT |
| General Cargo Ship | 31,948 | 0.7125 | 14.34 | 3,000 - 40,000 DWT |
| Refrigerated Cargo Carrier | 26,060 | 0.6496 | 23.10 | 3,000 - 25,000 DWT |
| Combination Carrier | 12,199 | 0.6298 | 13.39 | 4,000 - 200,000 DWT |
| LNG Carrier | 9.827 | 0.6200 | 0.01 | 100,000 - 250,000 DWT |
| Ro-Ro Passenger Ship | 3,264 | 0.6277 | 3.67 | 1,000 - 60,000 GT |
| Ro-Ro Cargo Ship | 17,807 | 0.6450 | 16.59 | 10,000 - 50,000 DWT |
*Reference line calculated at 50,000 DWT capacity
Carbon Intensity Indicator (CII) is a measure of a ship's carbon efficiency, expressed in grams of CO2 emitted per cargo-carrying capacity and nautical mile. It's mandatory under IMO's MARPOL Annex VI for ships of 5,000 GT and above engaged in international voyages.
Ships receive an annual rating from A (best) to E (worst) based on their CII performance relative to reference lines. The required CII level becomes more stringent each year, with a 20% reduction target by 2030 compared to 2019.
Superior
≤86% of reference
Good
≤94% of reference
Moderate
≤106% of reference
Lower
≤118% of reference
Inferior
>118% of reference
- A-C Rating: Compliant, no action required
- D Rating: 3-year limit, then corrective plan needed
- E Rating: Immediate corrective action plan required
- Documentation: SEEMP Part III required for all ships
2019-2022
1-3%
2023
5%
2024
7%
Current2025
9%
2026-2029
11-17%
2030
20%
- •Start monitoring CII early - reference lines tighten every year
- •Slow steaming is the fastest way to improve CII rating
- •Consider charter party clauses that share CII improvement benefits
- •Use voyage optimization software to reduce fuel consumption
- •Plan hull cleaning schedule around CII critical periods
- ✗Not preparing SEEMP Part III in time
- ✗Ignoring CII until rating drops to D or E
- ✗Focusing only on fuel efficiency, ignoring operational factors
- ✗Not considering CII in charter negotiations
- ✗Underestimating impact of waiting times and port congestion