.svg)
TL;DR: CII stands for Carbon Intensity Indicator the IMO's annual A–E rating of how much CO₂ a ship emits for the cargo it moves. Every cargo, RoPax and cruise ship of 5,000 GT and above gets a grade each year, and the required standard tightens annually. "CII" means different things in different sectors. In shipping it means one specific thing the Carbon Intensity Indicator the measure that now shapes how commercial ships are run.
What is CII in shipping?
CII — the Carbon Intensity Indicator measures how efficiently a ship turns fuel into transport: how much CO₂ it emits to move one tonne of its capacity one nautical mile. Introduced by the IMO under MARPOL Annex VI and in force since January 2023, it gives every large commercial ship an annual efficiency grade from A to E.
That's the "CII meaning" in one line: an operational carbon-efficiency score, calculated once a year from a ship's real fuel and voyage data. It's about how a ship is operated, not how it was designed.
What does CII measure intensity, not total
The key word is intensity. CII doesn't grade a ship on its total emissions; it grades efficiency the CO₂ it emits for the transport work it performs. In one line:
- Attained CII = annual CO₂ emissions ÷ (capacity × distance sailed)
The result is grams of CO₂ per tonne-mile, so a large ship run efficiently can score better than a small one run poorly.
What is a CII rating? (A to E)
Each ship's attained CII is compared against an IMO required value for its type and size, and the gap sets an annual grade the A–E rating a vessel earns each year:
- A — major superior: comfortably beating the requirement; a genuine selling point in fixtures.
- B — minor superior: ahead of the requirement, with headroom to spare.
- C — moderate: broadly on target; the minimum grade regulators consider acceptable.
- D — minor inferior: below the requirement; three consecutive Ds trigger a corrective action plan.
- E — inferior: well below the requirement; a single E triggers the corrective plan immediately.
The grade is based on the previous calendar year's verified data, so it can't be fixed retrospectively.
Does CII apply to your ship?
CII applies to cargo, RoPax and cruise ships of 5,000 GT and above in international trade, regardless of flag or owner there's no opt-out.
Why CII in shipping matters
The required standard tightens every year, so a ship doing exactly what it did last year drifts down the scale over time. And the grade is increasingly a commercial signal charterers, financiers and cargo owners all read it.
From understanding CII to managing it
Knowing what CII is matters less than knowing where your fleet stands against it before the year closes because a poor grade found in the new year is already locked in. That's what Emission Analytics is built for: it calculates attained CII continuously from validated data and forecasts each vessel's year-end grade, so CII becomes something you steer, not something you discover.
.svg)
.svg)
