Working out an excavation has two halves. The hole itself is a simple box — length times width times depth — and that "bank" volume is what you've removed from the ground. But once soil is dug it swells, loosening and taking up more room, so the loose volume you actually cart away is larger. The weight, by contrast, stays tied to the original in-ground volume because digging only spreads the same mass out. Put those together and you get the truck loads and tonnage to plan the haul.
Reviewed: June 19, 2026 · Author: Naveen P N, Founder — AI Calculator · Verified against: earthwork bank/loose-volume and bulking practice.
The excavation equations
The bank volume is the geometry of the hole. Swell — about 25% for common soil, less for sand, much more for rock — converts it to the loose volume you must store and haul. Weight uses the in-situ density (mass is conserved, so the loose material weighs the same, just spread out). Truck loads always round up, and on heavy wet soil the truck may reach its weight limit before its volume limit.
Worked example — a basement dig
Scenario: A 10 m × 5 m basement excavated 2 m deep in common soil (25% swell, 1,600 kg/m³), hauled in 10 m³ tippers.
The dig removes 100 m³ of soil weighing about 160 tonnes, but it swells to 125 m³ of loose spoil — so at 10 m³ a truck you need 13 loads, not 10. If the ground were rock at 50% swell, the same hole would produce 150 m³ loose and 15 loads, even though the in-place volume and weight are unchanged. Always quote haulage on the loose volume.
Frequently Asked Questions
bank = length × width × depth. A 10 × 5 × 2 m dig = 100 m³ in the ground. Split irregular shapes into prisms.
Dug soil loosens and bulks up: ~25% common soil, 10–15% sand, 50%+ rock. Loose volume = bank × (1+swell%).
loads = loose volume ÷ truck capacity, rounded up. 125 m³ loose in 10 m³ tippers = 13 loads. Use loose, not bank.
~1,600 kg/m³ for ordinary earth, so 100 m³ ≈ 160 t. Wet clay 2,000+, dry sand ~1,500. Based on in-situ volume.
Bank = in place; loose = swelled after digging; compacted = rolled in place (smaller than bank). Earthwork balances all three.