Excavation Calculator
Bank volume is the in-place volume you dig. Loose volume is what you must haul away, and it is larger because soil expands. A 30 x 20 x 5 ft trench in general soil (30% swell) gives 3,000 cu ft bank and 3,900 cu ft loose.
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Formula
- Bank volume = Length x Width x Depth x quantity
- Loose volume = Bank volume x (1 + swell factor)
- Swell volume = Loose volume - Bank volume
Worked Example
| Input | Value |
|---|---|
| Trench | 30 x 20 x 5 ft |
| Bank volume | 3,000 cu ft |
| Soil | General, 30% swell |
| Loose volume | 3,900 cu ft |
| Extra to haul | 900 cu ft |
| Bank in metric | 84.95 cubic metres |
Frequently Asked Questions
What is soil swell?
Soil expands when excavated because digging introduces voids. Sand swells about 15%, clay 25%, general soil 30% and blasted rock 50%.
What is the difference between bank and loose volume?
Bank volume is soil measured in place before digging. Loose volume is the same soil after excavation, and it determines truck loads.
How many cubic feet in a cubic metre?
One cubic metre equals 35.31 cubic feet.
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Estimates only. Quantities follow recognised standards (ACI 318, CRSI, IRC 2021, IS-1077, PBQS); actual site consumption varies with workmanship, wastage and detailing. Confirm with a licensed engineer before ordering.