How to calculate gravel
- Choose units; gravel is preselected.
- Enter the area's length and width (or diameter for a circle).
- Enter the depth: about 5 cm (2 in) for paths and decorative areas, 10–15 cm (4–6 in) for driveways.
- Read the volume, weight and number of bags or bulk bags.
From volume to tonnes
Gravel is usually sold by weight (tonnes or US tons) or by bulk bag, so the calculator converts volume to weight using a typical density of 1,600 kg per m³ (about 1.35 US tons per cubic yard). Washed pea gravel and crushed stone vary between about 1,500 and 1,800 kg/m³, so suppliers' figures may differ slightly. A 4 × 1 m path at 5 cm deep needs 0.2 m³, roughly 320 kg, or about 13 bags of 25 kg.
For driveways, lay gravel over a compacted sub-base of crushed hardcore and use a weed membrane; angular crushed stone locks together better than rounded pea gravel. Add 5–10% extra for settling. The calculator runs in your browser.
FAQ
How much does a cubic yard of gravel weigh?
About 1.3–1.5 US tons, depending on the stone.
How deep should a gravel driveway be?
10–15 cm (4–6 in) of gravel over a compacted base.
How many bags of gravel in a tonne?
About 40 bags of 25 kg.