When you need this calculation
Laying a path, patio base or driveway, filling a drainage trench, or topping up an existing gravel area. Volume tells you how much to order by the yard or cubic meter; weight tells you how many tons to order, and whether a pickup or trailer can carry it.
How the weight is worked out
First the volume: length × width × depth, with the depth converted from inches to feet (÷ 12) or from centimeters to meters (÷ 100). Then multiply the volume by the density of the gravel.
Gravel is sold loose, and loose gravel weighs much less than solid rock because of the gaps between stones. Typical loose densities run from about 1.4 to 1.8 tonnes per cubic meter, depending on the stone and its sizes. The calculator uses 1.6 t/m³ by default; choose your supplier’s figure if you have it.
Typical depths
Depth depends on use and on the ground underneath. As a rough guide, garden paths often use 2 to 3 inches (5 to 7.5 cm), while driveways are usually built in layers, with a coarse base of 4 inches or more under a finer top layer. Local building or road specifications take priority where they apply.
Common mistakes
Mixing up tons and tonnes. A US quote in tons and a UK quote in tonnes differ by about 10%. Use the US tons to metric tonnes converter to compare.
Using the density of solid stone. Rock itself is around 2.6 t/m³, but a pile of gravel is far lighter. Use a bulk (loose) density.
For soil and mulch, use the topsoil calculator and the mulch calculator.