CO₂ estimates for your shipments
Freight emissions are estimated from tonne-kilometres: shipment weight × distance × a mode factor. This calculator uses the well-to-wheel (WTW) default factors below, from the UK Government's DESNZ (DEFRA) greenhouse-gas conversion factors — the same family of defaults used in the GLEC Framework for logistics reporting.
| Transport mode | Factor (kg CO₂e per tonne-km) | Planning notes |
|---|---|---|
| Truck (FTL) | 0.097 | Articulated HGV, average laden. Part-loads and LTL run higher per tonne-km; vans much higher. |
| Ocean (container ship) | 0.020 | Average container ship. Slow steaming and large vessels run lower. |
| Air freight | 0.666 | International air freight, excluding the extra radiative-forcing uplift some reports add. |
| Rail | 0.033 | Average freight train; electric traction on a clean grid runs lower, diesel higher. |
Earlier versions of this page used unpublished rough factors that overstated emissions roughly 2.5–6× versus these published defaults; results were corrected in November 2026. Factors are planning averages: actual emissions vary with load factor, empty running, vehicle/vessel type, fuel and route, and a carrier's measured fuel data (primary data under ISO 14083) always beats a default factor. The tree figure is a rough equivalence — one tree absorbs on the order of 21 kg of CO₂ per year.
The standard method (ISO 14083 / GLEC) is: emissions = weight (tonnes) × distance (km) × mode factor. A 10-tonne shipment moved 1,000 km by truck is 10 × 1,000 × 0.097 ≈ 970 kg CO₂e. The same shipment by container ship is ≈ 200 kg, and by air ≈ 6,660 kg — which is why mode choice dominates freight carbon, ahead of small routing tweaks.
Well-to-wheel (WTW) factors count both the fuel supply chain (well-to-tank) and combustion (tank-to-wheel). When you compare a quote or a sustainability claim, check which basis and which factor set were used — tank-to-wheel-only or older factors can make the same shipment look very different.