Gravel calculator
Find out how much gravel you need for a path, driveway or border. Enter the area and the depth and this calculator gives you the weight in tonnes, the number of bulk bags, and the coverage.
Gravel calculator
Enter your measurements in metres. Everything updates as you type, and nothing is sent anywhere.
Based on a gravel density of about 1.6 tonnes per cubic metre and bulk bags of around 800kg, with 5% added for waste. Loose decorative gravel is usually laid 40mm to 50mm deep; a driveway needs 50mm or more over a proper sub-base.
Common questions
How much gravel do I need?
Multiply the area by the depth to get the volume, then by the density, about 1.6 tonnes per cubic metre, for the weight. At 50mm deep, one tonne of gravel covers roughly 12 square metres.
How deep should gravel be?
About 40mm to 50mm for a path or decorative area, and 50mm or more for a driveway laid over a compacted sub-base so it does not sink or rut. Too deep and it feels loose underfoot and spills over the edges.
How many bulk bags of gravel do I need?
A bulk bag holds roughly 800kg, which is about half a cubic metre, or enough to cover around 10 square metres at 50mm deep. The calculator rounds up to whole bags so you do not come up short.
These are independent guide prices based on typical UK jobs in 2026. Your actual cost depends on your property, spec, access and where you live. Always get at least three written quotes before committing. These quantities are a guide to help you order. Always round up and check with your supplier before buying.