Container shipping: carbon footprint per tonne-km
Live factor value
0.01612 kgCO2e per tonne-km
Source: UK DESNZ greenhouse-gas conversion factors, 2026 (revision 2). Factor set desnz-2026-r2.
Container ships are the quiet efficiency champions of world trade: the official DESNZ 2026 average factor, live below, is the lowest of the mainstream freight modes — each tonne-kilometre at sea costs roughly a sixth of the same tonne-kilometre in an average HGV. Scale is the whole story: a single large vessel moves tens of thousands of tonnes at once.
That per-tonne-km efficiency is why 'shipped from China' is usually a smaller slice of a product's footprint than intuition suggests: the sea leg often emits less than the delivery van at the end. The pressure points for shipping are its absolute scale and its fuel — the factor will track the industry's slow shift to cleaner propulsion.
Worked example
One tonne shipped Shanghai–Felixstowe (~19,000 tonne-km): 19,000 × 0.01612 = 306 kgCO2e.
Measure your own with the free freight calculator.
Frequently asked questions
- Is sea freight really lower-carbon than road?
- Per tonne-km, dramatically: the average container-ship factor sits below rail freight and roughly six times below average HGV road haulage in the same DESNZ tables.
- Does ship size matter?
- Yes — DESNZ publishes factors by vessel size, and the largest (8,000+ TEU) ships emit roughly a third as much per tonne-km as the smallest feeder vessels. The figure on this page is the all-sizes average.