Multiply the volume in cubic meters by the material’s density in tonnes per cubic meter. For example, 3 cubic meters of dry sand at a density of about 1.6 tonnes per cubic meter works out to roughly 4.8 tonnes. The result depends entirely on which material you’re converting, since density varies enormously between substances.

A cubic meter measures volume, while a tonne measures mass, and the relationship between the two depends on density. A cubic meter of water weighs about 1 tonne, but a cubic meter of steel weighs around 7.85 tonnes and a cubic meter of mulch weighs less than half a tonne. You always need to know the density of the specific material before converting.

Fresh water has a density of approximately 1 tonne per cubic meter (1,000 kg/m³) at standard temperature, which is why 1 cubic meter of water is often used as the simple reference point of 1 tonne when people first learn about this conversion.

Dry sand typically weighs around 1.6 tonnes per cubic meter, while wet sand can weigh closer to 1.9 tonnes per cubic meter because the water adds mass. Loose gravel is typically around 1.6 to 1.7 tonnes per cubic meter. These figures vary with moisture content, grain size and compaction, so they should be treated as estimates.

Standard wet-mix concrete weighs approximately 2.4 tonnes per cubic meter. The exact figure depends on the mix design, aggregate type and whether it’s measured wet or cured, so suppliers should be able to confirm the precise density for the mix you’re ordering.

A metric tonne equals 1,000 kilograms (about 2,204.6 lb). A US short ton equals 2,000 lb (about 907.2 kg), while a UK long ton equals 2,240 lb (about 1,016.0 kg). These three units are close but not identical, so it’s worth checking which one a supplier or invoice is actually using.

The densities used in this calculator are typical published approximations for each material and are intended for general planning purposes. Real-world density varies with moisture content, particle size, compaction, temperature and source, so for orders where precise weight matters, such as paying a haulier by the tonne, confirm the exact density with your supplier.

Yes. Divide the weight in tonnes by the material’s density in tonnes per cubic meter to get the volume in cubic meters. This calculator includes a toggle so you can convert in either direction using the same density figure.