Gravel calculator: cubic metres, cubic yards, tonnes, bags and truck loads of gravel, sand, topsoil or mulch for an area and depth.
Order 3.3 m³ (4.32 yd³) of gravel, about 5.54 t. In 0.5 ft³ bags that is 234 bags, or 1 truck load.
Loose bulk density from Engineering ToolBox; moisture can add 10–20%, so ask the supplier if you buy by weight.
Rounded up to whole bags and whole loads.
Volume is length × width × depth, plus an allowance for settling and compaction. Weight is that volume times the material's loose bulk density; the material list uses 1,680 kg/m³ for dry gravel, 1,555 for dry sand, 1,280 for loam and 400 for wood chips. Bags and truck loads are the volume divided by the bag or truck size, rounded up.
The default 10 × 3 m path, 10 cm deep, holds 3 m³. With 10% extra that is 3.3 m³ (4.32 yd³), about 5.5 tonnes of gravel, or 234 bags of 0.5 ft³.
Suppliers sell by the cubic metre, cubic yard or tonne. Density changes with stone size and moisture, so when you pay by weight, enter the supplier's figure under Other (enter density).
Checked against: Python decimal: 3 m³ × 1.1 = 3.3 m³ ÷ 0.764554857984 = 4.3162 yd³; × 1680 kg/m³ = 5.544 t; ÷ 0.5 ft³ bags = 233.08 → 234
Checked against: Hand calculation: 20 × 5 × 0.25 = 25 ft³ = 0.926 yd³; 25 ÷ 2 = 12.5 → 13 bags; 0.7079 m³ × 400 kg/m³
Checked against: Hand calculation: 27 ft³ = 1 yd³; 27 ÷ 0.75 = 36 bags exactly; 0.764555 m³ × 1280 kg/m³ = 0.9786 t
Checked against: Python decimal: 4 × 2 × 0.05 = 0.4 m³; 100 lb/ft³ = 1601.85 kg/m³ → 0.6407 t; 400 L ÷ 40 L = 10 bags
Multiply length × width × depth to get volume, then add an allowance for compaction; this calculator adds 10% by default. A 10 × 3 m area 10 cm deep is 3 m³, or 3.3 m³ with the extra. In feet, divide cubic feet by 27 to get cubic yards: 20 × 5 ft at 3 in deep is 25 ft³, or 0.93 yd³.
About 1.28 tonnes (1.42 US tons) at the 1,680 kg/m³ this calculator uses for dry gravel, because a cubic yard is exactly 0.764554857984 m³. At the same density a cubic metre weighs 1.68 t. Dry sand at 1,555 kg/m³ comes to 1.19 t per cubic yard and loam at 1,280 kg/m³ to 0.98 t; wet material weighs more.
54 bags of 0.5 ft³, because a cubic yard is 27 ft³. Bags of 2 ft³ take 13.5 per cubic yard, and 50 L bags take 15.3, since a cubic yard is 764.6 L. For a whole job, divide the volume to order by the bag size and round up, as the Bags result does.
108 ft² at 3 in deep, 162 ft² at 2 in and 324 ft² at 1 in, because a cubic yard is 27 ft³ and coverage is volume divided by depth. In metric, 1 m³ covers 20 m² at 5 cm and 10 m² at 10 cm. Add the settling allowance on top when ordering.
Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 4 worked examples whose answers come from independent sources; for example, “10 × 3 m gravel path, 10 cm deep, 10% extra” is checked against Python decimal: 3 m³ × 1.1 = 3.3 m³ ÷ 0.764554857984 = 4.3162 yd³; × 1680 kg/m³ = 5.544 t; ÷ 0.5 ft³ bags = 233.08 → 234.
Engineering ToolBox — Dirt and mud densities (gravel, sand, loam); Engineering ToolBox — Densities of common products (wood chips, bark).
4 worked examples with independently sourced answers ship with this calculator. They run in the test suite; you can run them here too.
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