🚜 Excavation Volume

Written and maintained by the PhDino author · Last reviewed 21 September 2026 · Checked against 1 independent reference calculation · how PhDino checks its numbers

Working out cut volume and how many truck loads it takes to haul the spoil off site.

Soil sitting undisturbed in the ground (bank volume) has been compacted by its own weight, and often by whatever was built on top of it, over a long time. The moment it's dug up, that structure is broken apart and the soil particles no longer pack as tightly — so the same mass of soil now occupies more volume. This is called swell, and it's why "I dug a 10 cubic yard hole" and "I have 10 cubic yards of dirt to haul away" are two different numbers.

Swell varies with soil type: loose sand swells relatively little, while a dense clay can swell substantially more, since clay's particle structure collapses more dramatically once disturbed. When in doubt, a conservative (higher) swell factor avoids showing up with too few trucks.

Key formula

Bank volume (yd³) = Length × Width × Depth ÷ 27
Trucked volume = Bank volume × (1 + swell %)
Truck loads = Trucked volume ÷ truck capacity, rounded up

Notes & limitations

• This assumes a simple rectangular cut at a uniform average depth — a sloped or irregular excavation needs to be broken into simpler volumes (or averaged carefully) first.
• Material that will be reused as backfill on the same site doesn't need to be hauled at all — this calculator is really about the portion of spoil actually leaving the site.