An excavation volume has two figures: the bank volume you dig out (length × width × depth) and the larger loose volume you haul away once the soil swells. This calculator gives both, in cubic yards and cubic metres, plus a truckload estimate.
Reviewed: June 20, 2026 · Author: Naveen P N, Founder — AI Calculator · Verified against: earthwork volume & swell relations, recomputed in code.
Bank vs loose volume
Soil is compacted in the ground, so the volume you dig by dimension is the bank volume. Once excavated it fluffs up — the swell factor — and the loose volume is what fills trucks and spoil heaps. Common soil swells about 25%, sand and gravel 12–15%, and clay 30% or more. Divide the loose volume by your truck capacity (a 10 yd³ truck is typical) and round up for the number of loads.
Worked examples
Trench 30 ft × 4 ft × 6 ft, 25% swell:
Pit 10 m × 2 m × 1.5 m, 25% swell:
Same trench in clay (35% swell):
The bank volume is what you'd order backfill or stone against; the loose volume is what you pay to haul and dispose. Clay's higher swell means more truckloads for the same hole.
Frequently Asked Questions
L × W × depth for bank volume. 30×4×6 ft = 720 ft³ = 26.67 yd³.
Expansion when dug: common soil ~25%, sand/gravel 12–15%, clay 30%+.
Bank = in-ground (by dimension); loose = after swell, what you haul.
Loose volume ÷ truck capacity, rounded up. 33 yd³ ÷ 10 ≈ 4 loads.
Deep trenches may need sloped walls or shoring — a safety requirement that adds volume.