Calculate the tonnage and volume of any aggregate – gravel, sand, ballast, MOT or crushed stone.
This aggregate calculator estimates how much aggregate (crushed rock, stone or fill) you need by area and depth, using the right density for the material you choose. It reports volume in cubic metres and cubic yards plus weight in tonnes/tons and bulk bags – metric or imperial.
| Aggregate (UK / US) | Approx. density |
|---|---|
| MOT Type 1 / crusher run (road base) | ~2.0 t/m³ |
| Ballast (sand & gravel mix) | ~1.8 t/m³ |
| Gravel / pea shingle | ~1.5 t/m³ |
| Sand | ~1.6 t/m³ |
A sub-base 5 m × 4 m at 150 mm of MOT Type 1 = 20 m² × 0.15 m = 3 m³. At ~2.0 t/m³ that's about 6 tonnes, or roughly 7 bulk bags. Add 10–15% because it compacts down when whacked (plate-compacted).
Multiply length × width × depth to find the volume, then multiply by the material density to get the weight in tonnes. Pick your material above and this calculator does it automatically.
A bulk bag holds around 850 kg. As a rough guide it covers about 10 m² at 50 mm deep, depending on the material.
Compacted sub-bases like MOT Type 1 are the heaviest at around 2.1 tonnes per cubic metre, while loose gravel and topsoil are lighter at 1.4–1.5 tonnes.
Most aggregates weigh around 1.5 tonnes per cubic metre, ranging from about 1.4 for loose gravel to 1.6 for MOT Type 1. The calculator uses a realistic density for each material.
About 50 mm (2 in) is typical for a decorative topping, while a driveway sub-base usually needs 100–150 mm (4–6 in) compacted.
