CO₂ of your shipment
Transport is where an importer's carbon sits. Enter weight, distance and mode, plus the road legs on either side of the main leg, and see what the whole journey costs door to door in CO₂e; and what switching the main leg to sea would save. Runs in your browser; nothing is sent anywhere.
Estimates for comparing options, not for regulatory reporting: these are transport-emission factors, and they are not all on the same basis; the note under the calculator says which is which. CBAM embedded emissions of the goods themselves are a different calculation and a different regime; see
the CBAM answer.
The calculation
The factors, and where each one comes from. All in kg CO₂e per tonne-km. Sea 0.016 is the DEFRA/DESNZ 2025 Freighting goods factor for a container ship averaged over all vessel sizes (0.016142). It is a direct, tank-to-wheel figure: DEFRA reports the upstream production of the fuel in a separate well-to-tank table, and that is not included here. Air 0.608 is the GLEC Framework v3.2 default for a long-haul freighter and is well-to-wheel. So the two are not on the same basis, and the air-versus-sea gap this calculator shows is not a like-for-like ratio. Road 0.062 and rail 0.028 are round orientation figures for a European average; a real lane moves a long way with the vehicle, the load factor and, on rail, the power mix, so use your carrier's own factor where the number has to hold up. Choose the mode you would otherwise use to see the saving. Checked 5 September 2026; the DESNZ 2026 set was published on 11 June 2026 and the sea figure has not yet been re-checked against it.
Door to door, and an honest comparison. The headline figure is the whole journey: the main leg in the mode you chose, plus the inland road legs on either side of it, at the same road factor as the truck option above. When the page says what switching to sea would save, the road legs stay in both sides of that sum, because exchanging the ocean leg does not remove the trucks; the saving shown is one you could actually book. Leave the road-legs field at zero and the answer is the main leg alone, as before.
Vessel size moves the sea figure more than anything else. 0.016 is an average over all container-ship sizes. A large deep-sea vessel sits well below it and a small feeder well above it, so a real deep-sea lane is cleaner per tonne-km than this page shows, and a feeder leg is dirtier. Short-haul air freight is not offered as a mode: the figures in circulation for it could not be tied to a published set, and under about 1,500 km there is no container ship to compare it with anyway.
The last two rows use round orientation figures, written out here so the arithmetic is checkable: 120 g CO₂ per car-kilometre and 22 kg CO₂ taken up per tree-year. They exist to make the number tangible; they are not a measurement of your shipment, and the calculator uses exactly the two figures printed in this sentence.
The air factor is CO₂e from producing and burning the fuel. It does not include the non-CO₂ effects of aviation at altitude (contrails, nitrogen oxides): the GLEC Framework v3 aviation chapter expressly leaves out the additional warming from burning aviation fuel at altitude, and factor sets that add a radiative-forcing uplift put air freight higher still. Counting those effects widens the air-versus-sea gap, never narrows it.