Gravel Calculator
Enter the area and depth to get the gravel volume in cubic metres, plus an approximate weight in tonnes using a typical density — handy when suppliers quote by the tonne.
Enter your measurements
Your m³ of gravel result will appear here instantly.
How to use this calculator
- 1
Measure the length and width of the area to be covered.
- 2
Choose your depth: 75–100 mm for driveways over a compacted road base, 40–50 mm for decorative pebbles in garden beds.
- 3
Leave the density at 1,600 kg/m³ unless your supplier states a different figure for the product.
- 4
Compare the tonnage against the supplier's price per tonne — most landscape yards sell gravel by the tonne, not the cubic metre.
- 5
Order 5–10% extra for spread losses and settling, especially on driveways.
How the calculation works
Volume
Length × width × depth gives cubic metres, the same as any other loose material.
Weight
Volume × density gives the weight. Gravel densities vary by stone type and size: fine crushed rock is denser than large rounded pebbles. The 1,600 kg/m³ default is a reasonable middle figure; at that density, 1 m³ weighs about 1.6 tonnes.
Worked example
A driveway 10 m × 3 m at 75 mm deep.
Volume = 10 × 3 × 0.075 = 2.25 m³.
Weight = 2.25 × 1,600 kg = 3.6 tonnes.
Order approximately 2.3–2.5 m³, or about 3.7–4 tonnes, depending on how your supplier sells it.
Frequently asked questions
How deep should gravel be for a driveway?
A common approach is 75–100 mm of gravel over a compacted road base of 100 mm or more. Decorative pebble beds only need 40–50 mm — deep enough to cover the weed matting below, shallow enough not to disappear into the soil over time.
Why do suppliers sell by the tonne?
Loose bulk products are weighed at the loader, not measured. That's why the density matters: two products can both fill 1 m³ but weigh 1.4 vs 1.8 tonnes. When a supplier quotes $X per tonne, convert your volume using the density to compare prices fairly.
How much area does one tonne of gravel cover?
At a typical 1,600 kg/m³, one tonne is 0.625 m³, which spreads to about 12.5 m² at 50 mm deep, or 6.25 m² at 100 mm. Use the calculator rather than guessing — deep cover is the most common over-order mistake.
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Results are estimates only. Always confirm material requirements with your supplier or a qualified professional before purchasing.