- 4.8m²per tonne at 100mm
- ~4m²per 850kg bag at 100mm
- 2.1 tper m³ compacted
- 0.21 tper m² at 100mm
MOT Type 1: tonnes to m²
Compacted depth, no allowance for waste (add 5–10%).
| Compacted depth | m² per tonne | m² per 850kg bag | Tonnes per m² | Typical use |
|---|---|---|---|---|
| 50 mm | 9.5 | 8.1 | 0.11 | Topping up an old base |
| 75 mm | 6.3 | 5.4 | 0.16 | Paths on firm ground |
| 100 mm | 4.8 | 4.0 | 0.21 | Patios, shed bases |
| 150 mm | 3.2 | 2.7 | 0.32 | Driveways, clay ground |
The sum
m² per tonne = 1 ÷ (2.1 × depth in metres)
100mm: 1 ÷ (2.1 × 0.1) = 4.8m²
The MOT Type 1 calculator turns your area into tonnes and bulk bags, with membrane and compaction layers.
