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NIST Verified Standards

Excavation & Backfill Calculator — Dirt Volume & Hauling Estimator

Calculate trench, hole, or foundation excavation volume in cubic yards. Adjusts for bank soil density, spoil swell expansion, and backfill compaction requirements.

Soil in its natural undisturbed state is measured in Bank Cubic Yards (BCY). Once excavated, dirt expands to a larger volume measured in Loose Cubic Yards (LCY) due to added air (spoil swell). A standard dump truck holds exactly 10 cubic yards.

Excavation Volume Calculator
Bank vs. Loose Density Sizing
Earthwork Material Output
Volume Class
Cubic Feet (ft³)
Cubic Yards (yd³)
Required Material / Loads
Bank Volume (Undisturbed)
4,000 ft³
Bank Cubic Yards (BCY)
148.1 BCY
Loose Spoil Volume (+Swell)
4,600 ft³
Loose Cubic Yards (LCY)
170.4 LCY
Compacted Backfill (-Compaction)
3,400 ft³
Dump Truck Loads Needed
18 Loads
Soil Swell advisory: Loose dirt swells by 22.2 yd³ from bank excavation. ✔ EARTHWORK STABLE

Understanding Soil Swell and Compaction

Experienced site superintendents know that dirt occupies different physical space depending on its compaction state:

Key Volume Equations:
Bank Volume (BCY) = (Length × Width × Depth) ÷ 27
Loose Volume (LCY) = Bank Volume × (1 + (Swell% ÷ 100))
Compacted Volume (CCY) = Bank Volume × (1 - (Compaction% ÷ 100))
Dump Truck Loads = Ceil( Loose Volume (LCY) ÷ Truck Capacity )

Standard Soil Density & Swell Chart

Soil Classification Swell Factor % Compaction Shrink % Common Application
Clean Sand / Gravel 10% - 15% 10% - 15% Backfilling slabs, foundation drainage.
Common Earth / Topsoil 15% - 20% 15% - 20% Standard residential lawn & general site prep.
Heavy Clay 20% - 25% 20% - 25% Ponds, structural sub-bases. High expansion danger.
Hard Rock / Blast Spoil 30% - 40% 0% (Varies) Rock fill layers, retaining walls. Very high swell.
Soil weight expansion ratios verified under construction standards.