Calculate the volume of soil to excavate and the number of skip loads or truck loads needed.
This excavation calculator works out how much soil (spoil) you'll dig out of a hole, trench or foundation, and how much you'll need to haul away once it “swells”. Dug soil expands in volume, so the loose (truck) volume is always bigger than the in-ground (bank) volume. Results are shown in cubic yards and cubic metres, with truck/skip loads – in metric or imperial.
| Material | Swell |
|---|---|
| Sand / gravel | 10–15% |
| Common earth / topsoil | 20–30% |
| Clay | 30–40% |
| Rock | 40–70% |
A trench 10 m × 0.6 m × 1 m deep = 6 m³ bank volume. With clay at 35% swell, the loose volume is about 8.1 m³ – roughly 1½ builder's skips (dumpsters). Excavated earth weighs roughly 1.3–1.5 tonnes per m³, so plan haulage accordingly.
When soil is excavated, it breaks apart and occupies more space than when compacted in the ground. The swell factor accounts for this increase – typically 20–30% for common soil.
A standard dump truck holds about 10 cubic yards (7.6 m³). Larger trucks can carry 14–18 cubic yards.
Loose soil typically weighs 1.1–1.5 tons per cubic yard (1.3–1.8 tonnes per m³) depending on moisture and soil type.
Multiply length × width × dig depth for the in-ground volume, then add the swell factor (20–30%) to estimate the loose spoil you will actually cart away. This calculator does both steps for you.
Clean topsoil can often be reused for landscaping or levelling, but subsoil, clay and any contaminated or hardcore-mixed spoil usually has to be removed. Separating topsoil as you dig cuts how much you pay to take away.
