Excavation Calculator
Calculate bank cubic yards, loose volume with bulking factor, truck loads, and haul-off cost for rectangular excavations.
Excavation
Bank volume, loose volume, truck loads, and haul-off cost
Inputs
Sandy loam 25% · Clay 30% · Rock 40%
Tandem ≈ 14, Super-B ≈ 20
Per truck trip (not per cu yd)
Results
How to Use the Excavation Calculator
Enter the excavation length, width, and depth. Select soil type to set the bulking factor. Enter truck capacity and cost per load for haul-off pricing. The calculator returns bank cubic yards, loose cubic yards after bulking, number of truck loads, and total haul cost.
How It Calculates
Loose CY = Bank CY × (1 + Bulking% / 100)
Loads = ceil(Loose CY / Truck Capacity CY)
Haul Cost = Loads × Cost per Load
Bulking defaults: Sandy loam 25% · Clay 30% · Rock 40%. Haul cost is priced per load (truck trip), not per cubic yard.
What to Know Before You Calculate
- Add working room: Excavation dimensions should include working room beyond the foundation footprint — typically 2–3 ft per side for formwork access.
- Verify soil type: Bulking factor significantly affects load count. Clay and silty soils bulk more than sandy material. Rock can bulk up to 50%.
- Haul vs. stockpile: Some soil can be stockpiled on site for backfill, reducing haul-off loads. Only calculate haul-off for material that leaves the site.
- Tipping fees: Haul-off cost typically includes both trucking and tipping (disposal) fees. Confirm what is included in the contractor's per-load price.
Common Mistakes
- Using the foundation footprint dimensions. Always add working room. The excavation is always larger than the building foundation.
- Calculating truck loads from bank cubic yards. Trucks carry loose material. Always convert to loose CY before calculating loads or you will underestimate loads by 25–40%.
- Ignoring over-excavation. Soft spots, obstructions, or grade variation often result in 10–20% more excavation than the theoretical calculation.
- Not accounting for backfill. Some of the excavated material returns as backfill. Calculate net haul-off after subtracting estimated backfill volume.
Frequently Asked Questions
What is the difference between bank cubic yards and loose cubic yards?
Bank cubic yards (BCY) is the volume of soil in its undisturbed, in-place state. Loose cubic yards (LCY) is the volume after excavation — soil expands (bulks) when disturbed. Sandy loam bulks ~25%, clay ~30%, rock ~40%. Trucks are loaded by loose volume, so always convert to LCY for haul calculations.
How many cubic yards of dirt fit in a dump truck?
A standard tri-axle dump truck carries 10–14 loose cubic yards depending on truck capacity and payload limits. This calculator defaults to 10 cu yd per load, which is conservative and safe for estimation. Confirm truck capacity with your haul contractor.
How do I calculate excavation volume for a foundation?
Measure the excavation cut length, width, and depth. Volume (BCY) = L × W × D / 27. For a basement: L = building length + 2 ft each side working room, W = width + 2 ft each side, D = foundation depth + 12 inches for subbase.
Is haul-off cost calculated per cubic yard or per truck load?
In practice, contractors price haul-off per truck load (per trip), not per cubic yard. Each truck load is a fixed charge regardless of how full the truck is. This calculator uses cost per load, which matches how haul contractors quote work.
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Disclaimer: Excavation volumes are estimates based on rectangular geometry. Actual volumes vary due to slope, over-excavation, and soil conditions. Haul costs are estimates only — confirm pricing with your excavation and haul contractor.
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