Gravel Calculator
Calculate volume and weight of gravel needed for paths, driveways, and garden beds
Length (m)
m
Width (m)
m
Depth (cm)
cm
Recommended: paths 5–10 cm, driveways 10–15 cm
Gravel Type
Materials Needed
Volume
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Weight
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Bags Needed
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How to Calculate Gravel
Gravel quantity is calculated by volume (length × width × depth) then converted to weight using the material's bulk density. Dry gravel is about 1,680 kg/m³; wet or compacted gravel is closer to 2,000 kg/m³. For garden paths, 5–10 cm depth is typical; driveways need 10–15 cm.
Order slightly more than calculated to account for compaction and settling — typically add 10–15% extra. Gravel is often sold in bulk (per tonne) or in 25 kg or 50 kg bags for smaller quantities.
lightbulb Example
10m × 3m path, 8 cm deep:
1Volume: 10 × 3 × 0.08 = 2.4 m³
2Weight: 2.4 × 1,680 = 4,032 kg
✓ ~4 tonnes, or 162 × 25 kg bags
quizFrequently Asked Questions
How much gravel do I need per square metre?
For a 50 mm (2-inch) deep layer, you need 0.05 m³ per m². A 10 m × 5 m driveway with a 50 mm layer requires 10 × 5 × 0.05 = 2.5 m³. Add 10–15% for wastage and compaction. Loose gravel compacts by about 15–20% when settled, so always order slightly more than calculated.
What size gravel is best for driveways?
20–25 mm (¾ inch) gravel is ideal for driveways — small enough to bind together, large enough to resist displacement under tyres. For pathways, use 10–14 mm pea gravel. For drainage layers under slabs, use 20–40 mm crushed stone. Avoid very fine gravel (less than 6 mm) for driveways as it scatters easily.
How heavy is gravel per cubic metre?
Gravel density is typically 1,600–1,700 kg/m³ (1.6–1.7 tonnes per m³). A standard truck carries 6–8 tonnes, which equals roughly 4–5 m³ of gravel. For small quantities, a 50 kg bag covers approximately 0.03 m³ at 50 mm depth. Use these figures to estimate delivery quantities and costs.