Quick answer: A 5 m × 4 m area 10 cm deep needs 5 × 4 × 0.10 = 2 m³ of gravel; at a bulk density of 1,600 kg/m³ that weighs 3.2 tonnes.
How it's calculated
Volume = length × width × depth, all in metres. Weight = volume × bulk density, the weight of one cubic metre of the loose material as delivered, including the air between stones.
Bulk density depends on the stone, its size and moisture, so it is an input here. Ask your supplier for the figure of the material you are buying; quarries in the Gulf usually sell aggregate by the tonne or by the truckload. Some calculators preset a density for each material (for example about 1,680 kg/m³ for gravel), so their tonnage can differ for the same volume.
Compacted base layers settle, so add a few percent if you will compact the gravel. In US units, 1 lb/ft³ = 16.018 kg/m³ and a short ton is 2,000 lb.
Worked examples
- 5 m × 4 m × 10 cm at 1,600 kg/m³: 2 m³ × 1,600 = 3,200 kg = 3.2 t
- 12 ft × 10 ft × 3 in at 100 lb/ft³: 30 ft³ = 1.11 yd³ → 3,000 lb = 1.5 short tons
Volume per 10 m² by depth
| Depth | Volume | Weight at 1,600 kg/m³ |
|---|---|---|
| 5 cm | 0.5 m³ | 0.8 t |
| 7.5 cm | 0.75 m³ | 1.2 t |
| 10 cm | 1 m³ | 1.6 t |
| 15 cm | 1.5 m³ | 2.4 t |
| 20 cm | 2 m³ | 3.2 t |
Frequently asked questions
How many tonnes is one cubic metre of gravel?
It equals the bulk density in tonnes: at 1,600 kg/m³, one cubic metre weighs 1.6 tonnes. Check the supplier's figure for your material.
How deep should a gravel driveway be?
Driveways are commonly built in layers totalling 10–15 cm or more over a compacted base; paths and decorative beds use about 5 cm.
How do I convert cubic yards to cubic metres?
Multiply by 0.7646. One cubic metre is 1.308 cubic yards.
How much gravel do I need for 10 m²?
At 5 cm deep you need half a cubic metre, roughly 0.8 tonnes. At 10 cm it's a full cubic metre, about 1.6 tonnes, assuming 1,600 kg per m³.
Should I lay fabric under gravel?
Under decorative gravel, yes. A weed membrane keeps weeds down and stops the stones sinking into the soil. A driveway is different: it needs a compacted base, not fabric on its own.
Which type of gravel should I use?
Angular crushed stone locks together, so it's the one for driveways and bases. Round pebbles look nice in a garden bed but roll underfoot. Your supplier can tell you which sizes they carry.