RightShip GHG Rating

A–G letter grade comparing a ship's EEDI to peer ships of similar type and size. Used by 90%+ of dry-bulk and tanker charter decisions. Grade A is top 10 %; B 10-30 %; C 30-60 %; D onward increasingly below-peer.

PortIndexRightShip

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This calculator requires JavaScript to compute its result. The formula, symbols, and regulatory sources are shown in the Formula section below.

Formula, assumptions, and limits

z = \frac{\text{EEDI}_\text{peer} - \text{EEDI}_\text{ship}}{\sigma_\text{peer}}

Symbol	Meaning	Unit
$\text{EEDI}_\text{ship}$	Attained EEDI / EEXI of the ship	g / (t·nm)
$\text{EEDI}_\text{peer}$	Peer-group mean EEDI	g / (t·nm)
$\sigma_\text{peer}$	Peer-group standard deviation	g / (t·nm)
$z$	Z-score	σ

Source: RightShip - *GHG Rating methodology*; IMO Resolution MEPC.328(76) - EEDI / EEXI

In short

Compute a ship's RightShip A–G GHG letter grade from its EEDI vs peer-group mean and standard deviation.

Learn the theory Shipping Climate Finance and GHG Ratings