Gravel Calculator
Calculate exactly how many cubic metres and tonnes of gravel, crushed rock, road base, blue metal or sand you need for any area. Works for driveways, paths, drainage and landscaping. Metric and imperial.
🔨 Gravel Calculator
📐 How It Works
Gravel volume is calculated by multiplying the area by the depth. The volume is then converted to tonnes using the material's bulk density. Different materials have different densities — road base compacts more than loose pea gravel. Always add 10% waste for spreading and compaction losses.
📋 Worked Example
A 15m × 3m driveway at 120mm depth using road base (1.7 t/m³): Volume = 15 × 3 × 0.12 = 5.4 m³. With 10% waste = 5.94 m³. Tonnes = 5.94 × 1.7 = 10.1 tonnes. At $68/tonne = $687.
❓ Frequently Asked Questions
At 100mm depth: 0.16–0.18 tonnes/m² for crushed rock. At 150mm: 0.24–0.27 tonnes/m². At 200mm: 0.32–0.36 tonnes/m². The exact amount depends on the material density and whether it is compacted.
For a residential driveway: 100–150mm of compacted road base. For heavy vehicles: 150–200mm. For a decorative gravel path: 50–75mm. Gravel compacts 20–30% when rolled, so order accordingly.
Crushed rock / blue metal: 1 tonne ≈ 0.63 m³. Road base: 1 tonne ≈ 0.59 m³. Pea gravel: 1 tonne ≈ 0.67 m³. River pebble: 1 tonne ≈ 0.71 m³. Bulk density varies, so always confirm with your supplier.
Small trailer (6×4): 0.5–1 tonne. Large trailer: 1.5–2 tonnes. Small rigid truck: 5–6 tonnes. Semi-trailer: 20–25 tonnes. For large quantities, a semi-trailer delivery is the most cost-effective option.