Free Tool
CII Rating Estimator
Enter an attained CII and see where it lands on the A–E rating band — built on the IMO reference lines and boundary vectors, all 12 ship-type categories, 2023–2026 reduction factors.
Boundaries: required 3.792 × dd vectors [3.261, 3.565, 4.020, 4.475]. Reference line uses capacity 82,000 DWT. Indicative estimate per IMO MEPC.353(78)/.354(78)/.338(76) — the official rating is computed and verified from your IMO DCS submission; reduction factors beyond 2026 are not yet adopted.
How it works
Reference lines, reduction factors, boundaries.
The math
Required CII = (1 − z) × a × Capacity^(−c), where a and c are the ship-type reference-line parameters (MEPC.353(78), G2) and z is the annual reduction factor — 5/7/9/11% for 2023–2026 (MEPC.338(76), G3). The attained CII is then scored against four boundaries: required × the dd vectors from MEPC.354(78) (G4).
Reading the band
A = major superior, B = minor superior, C = moderate, D = minor inferior, E = inferior. A ship rated D for three consecutive years, or E in any year, must include a corrective action plan in its SEEMP Part III. Factors for 2027–2030 are not yet adopted — IMO is reviewing them.
Sources and caveats
Resolutions MEPC.353(78), MEPC.354(78), MEPC.338(76) and MARPOL Annex VI reg. 28. The official rating derives from verified IMO DCS data (fuel consumed, distance, capacity) — attained CII here is your input, so treat the band as an indication, not a certification. Correction factors and voyage adjustments can change the attained value.
Get in touch
Carbon intensity is a routing outcome.
Voyage Intel Pro helps planning teams weigh speed, route and emission-area context before the year is written to DCS.