Excavation Calculator

How to Calculate Excavation Volume & Truck Loads

Excavation estimates require understanding two key volumes: bank cubic yards (material in-place, undisturbed) and loose cubic yards (the expanded volume once dug up). The difference — called "swell" — determines how many trucks you actually need to haul away the spoils.

The Formula

For rectangular cuts: Bank CY = Length × Width × Depth ÷ 27. For trapezoidal cuts: Bank CY = (Top Width + Bottom Width) ÷ 2 × Depth × Length ÷ 27. Loose CY = Bank CY × (1 + Swell %). Truck loads = Loose CY ÷ Truck capacity.

Swell Factors by Soil Type

• Sand & gravel — 10–15% swell, easy to excavate and compact
• Loam / common earth — 20–30% swell, most residential site conditions
• Clay — 30–40% swell, heavy, sticky when wet, difficult to work
• Shale & soft rock — 40–65% swell, may require rock hammer
• Hard rock — 50–80% swell, blasting or hydraulic breaking required

Bank vs. Loose Measurement

Earthwork contracts specify whether payment is "bank measure" (in-place volume) or "truck measure" (loose volume). Bank measure is more common for excavation contracts. Loose measure is used for hauling. Always clarify with your client which measurement applies — the difference can be 25–40% of the total quantity.

Truck Sizing Guide

• Single-axle dump truck (10 yd³) — best for tight residential sites, lower weight on pavement
• Tandem dump truck (14 yd³) — most common for commercial earthwork
• Tri-axle dump truck (20 yd³) — maximum payload, requires good site access
• Always verify weight limits — wet clay can exceed truck weight capacity before filling the bed

Cut vs. Fill

When possible, balance your cut and fill on-site to minimize hauling. A "cut-to-fill" plan moves excavated material to another area of the site for grading, saving $15–$30 per cubic yard in hauling and disposal costs. Always test soil quality before using excavated material as structural fill.