Aggregate Calculator
Calculate Aggregate Needed
Typical: Patio base 100mm, driveway sub-base 150mm, paths 75mm
Density used: MOT Type 1 = 2.0 tonnes/m³, hardcore = 1.9 tonnes/m³, gravel = 1.7 tonnes/m³, sand = 1.6 tonnes/m³ (bulk loose). Compaction reduces volume by ~20%, accounted for in calculation. Aggregates typically sold in bulk bags (800kg-1000kg) or loose tonnes. Always order 5-10% extra for compaction and levelling.
How This Calculator Works
Aggregate tonnage = Volume (m³) × Density (tonnes/m³) × Compaction factor.
Aggregate Types Explained
- MOT Type 1: Crushed limestone/granite for sub-bases under driveways, patios, concrete slabs. Compacts well. Most common.
- Hardcore: Recycled crushed concrete/brick. Cheaper than MOT Type 1, suitable for light-use bases.
- Gravel: Decorative stone for driveways, paths, borders. Doesn't compact (needs edging).
- Sharp sand: Bedding layer for block paving, slabs. Not building sand (too fine).
Recommended Depths
| Application | Depth |
|---|---|
| Garden path | 75 mm |
| Patio base | 100 mm |
| Driveway (cars) | 150 mm |
| Driveway (heavy vehicles) | 200 mm+ |
| Sand bedding (paving) | 30-50 mm |
Buying Aggregate
Aggregates sold as:
- Bulk bags: Typically 800kg-1000kg (around 0.5 m³). Convenient for small projects.
- Loose tonnes: Delivered loose by lorry. Cheaper per tonne for large projects (3+ tonnes).
Related Guides
- Aggregate Calculator Guide — MOT Type 1 vs hardcore
- Concrete Calculator — for concrete over the sub-base