IMO CII · Calculator
IMO CII rating calculator
Attained CII, required CII and the A–E band for one ship-year, computed with the same engine and the same MEPC coefficients this site publishes.
Ship-year inputs
What this does and does not tell you
The rating is the attained annual operational CII of MARPOL Annex VI regulation 28 measured against the required CII for the year, using the reference lines of MEPC.353(78), the reduction factors of MEPC.400(83) and the rating boundaries of MEPC.354(78). The arithmetic is the one the platform runs, and the coefficients are the ones the resource hub cites, valid from 2023-01-01.
It does not apply the correction factors and voyage adjustments of MEPC.355(78) — the ice-class, ship-to-ship and other deductions a ship may be entitled to before its attained CII is assessed. A ship whose real filing takes those deductions will rate at least as well as this page shows, never worse.
Nor is it a verified figure: a rating that counts is calculated from the verified IMO DCS data for the year and confirmed by the administration or a recognised organisation.