Road Base Calculator

This calculator works out how much loose road base or crusher run to order to achieve a target compacted depth. Road base compacts significantly during installation — the compaction factor accounts for this, then the calculator converts the loose order volume into tonnes. For density-only checks, use the road base m3 to tonnes converter.

How to Use

1. Enter area: Total area to be covered in square meters.
2. Enter compacted depth: The finished depth after compaction — not the loose depth. Standard is 100–200mm for driveways.
3. Select compaction factor: 1.30 for standard applications, 1.35 for heavy traffic. Or enter a custom factor if you know your material's exact compaction ratio.
4. Set waste factor: 10% is standard. Applied after compaction factor.
5. Read order quantity: Loose m³ to purchase, plus weight in tonnes.

Formula

Compacted volume: Area (m²) × Compacted Depth (m)
Loose order volume: Compacted Volume × Compaction Factor
Order with waste: Loose Volume × (1 + Waste %)
Weight: Order Volume × 2.0 t/m³

Worked Example

For a 40 m² driveway needing 150mm compacted crusher run, the compacted volume is 6.0 m³. With a 1.30 compaction factor, order 7.8 m³ loose road base. Adding 10% waste gives 8.58 m³, which weighs about 17.16 tonnes at 2.0 t/m³.