tonne-mile

A shipping industry metric calculated by multiplying the volume of cargo carried by the distance traveled.

A tonne-mile is a primary metric used in the shipping, logistics, and transportation industries to measure total transport work and demand. It combines the physical weight of cargo in metric tons with the distance it is transported in miles. This metric is essential because measuring cargo volume alone (such as absolute tons shipped) fails to capture how long a vessel or vehicle is occupied on a voyage. For investors in maritime shipping equities (such as tankers, dry-bulk carriers, or container lines), changes in tonne-mile demand are highly influential. When trade routes lengthen due to geopolitical disruptions, canal closures, or shifting trade partners, vessels must travel longer distances. This effectively reduces the global supply of available ships, driving up charter and freight rates even if the absolute volume of global trade remains flat. Conversely, a decrease in tonne-mile demand—often caused by localized sourcing, the opening of shorter transit canals, or localized demand destruction—increases the active supply of vessels. This oversupply typically depresses shipping rates. Investors monitor this metric alongside fleet capacity growth to gauge the supply-demand balance of the global shipping market.

A dry-bulk carrier transports 50,000 metric tons of iron ore from Brazil to China, a voyage of 11,000 miles. The transport work performed is 50,000 tons multiplied by 11,000 miles, which equals 550,000,000 tonne-miles. If the same cargo were sourced from Australia instead, over a distance of only 3,500 miles, the work would drop to 175,000,000 tonne-miles, freeing up significant shipping capacity.