Carbon Emissions Estimator

A container ship carries tens of thousands of tonnes of cargo on a single voyage and burns fuel efficiently relative to that load, while an aircraft is weight- and speed-constrained and burns far more fuel per tonne of cargo carried over the same distance. That gap is why sea freight typically shows an emission factor roughly 40x lower than air freight per tonne-km in this tool, even though a specific shipment's real footprint depends on the vessel, aircraft, and route involved.

A tonne-km is the standard freight transport unit: one tonne of cargo moved one kilometer. It lets you compare emissions, cost, or capacity across shipments of different weights and distances on a common basis, which is why emission factors in freight are typically expressed as kg CO₂ per tonne-km rather than per shipment.

No — this is a screening estimate for comparing shipping options, not an audited emissions figure. For carbon accounting or disclosure, use an accredited methodology such as the GLEC Framework or ISO 14083, which require carrier- or lane-specific data this calculator does not collect.

The biggest lever is usually mode shift — moving cargo that can tolerate a longer transit time from air to sea or rail typically cuts emissions per tonne-km substantially. Consolidating multiple partial shipments into fewer, fuller loads also helps, since a half-empty truck or container still burns close to the fuel of a full one for the same distance.

They are screening-level, mode-average factors in the spirit of published GLEC- and IMO-style reference figures, not a live feed from any single source. Actual emissions per tonne-km vary by vessel or aircraft type, fuel, load factor, and route, so treat these numbers as a planning comparison between modes rather than a precise figure for any one shipment.