How much gravel do I need?

Multiply the area by the depth to get the volume in cubic metres, then multiply by the density to get tonnes. Gravel is usually around 1.5 tonnes per cubic metre. The calculator works out both from the area and depth you enter.

How deep should gravel be?

A path is often 50 mm deep, while a driveway is usually 75 to 100 mm or more over a compacted base. Deeper layers need more material. Enter the depth in millimetres for your job.

How many tonnes in a cubic metre of gravel?

Most gravel and crushed metal weighs about 1.5 tonnes per cubic metre, though it varies with the stone and how wet it is. The calculator lets you change the density if your supplier gives a different figure.

Gravel Calculator

Work out how much gravel, metal, or aggregate to order. Enter the area to cover and the depth, and the calculator shows the volume in cubic metres and the weight in tonnes. You can change the density if your supplier quotes a different figure for the product you are using.

Area (m²)

Depth (mm)

Density (tonnes per m³)

0 t

gravel needed

Volume0 m³

Order a little extra to allow for compaction and settling.

How it works

The volume is the area times the depth, with the depth converted from millimetres to metres. Multiply the volume by the density to get the weight in tonnes. Suppliers often sell by the cubic metre or by the tonne, so the calculator shows both.

Worked example

For 20 square metres at 75 mm deep, the volume is 20 times 0.075, which is 1.5 cubic metres. At 1.5 tonnes per cubic metre that is about 2.25 tonnes of gravel.

Related calculators

Concrete Calculator: concrete volume.
Cubic Metre Calculator: work out a volume.
Topsoil Calculator: soil for a garden.
Mulch Calculator: mulch for beds.

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