Earthwork & Excavation Calculator (Soil Volume)

Calculate the exact volume of soil to be excavated and estimate the number of truck trips required for soil removal.

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Earthwork Calculation: Estimate Excavation and Soil Removal Volume

The first physical step of any construction project is earthwork. Whether you are bringing in a JCB to dig foundation footings or excavating a full basement, an accurate excavation calculation helps you estimate heavy machinery costs and plan the logistics of removing the dug-up soil.

Important Earthwork Terminology

  • CFT (Cubic Feet): The primary volume measurement used in Indian construction.
  • Brass: A traditional Indian volumetric unit. 1 Brass = 100 CFT.
  • Bank Volume: The volume of soil in its natural, undisturbed state in the ground.
  • Loose Volume: The volume of soil after it has been excavated.

The "Swell Factor" (Why dirt expands)

A major mistake beginners make is assuming that a 100 CFT hole will produce 100 CFT of dirt. This is false!

In the ground, soil has been heavily compacted over thousands of years. When a machine excavates it, air is introduced, and the dirt breaks apart. This causes the soil to expand, increasing its volume. This expansion is known as the Swell Factor.

Standard Indian earth (loam or mixed soil) typically swells by 25%. This means that 100 CFT of solid earth will turn into 125 CFT of loose soil that you actually have to haul away!

How to Calculate Soil Removal Volume

Calculating your soil removal volume involves finding the total Bank Volume using basic geometry, and then applying the Swell Factor.

Step 1: Calculate Bank Volume (Solid Earth)
Formula: Length × Width × Depth × Number of Pits
Example: 5 ft × 5 ft × 6 ft = 150 CFT per pit.
If you have 10 identical pits: 150 × 10 = 1500 CFT of solid earth.
Step 2: Apply the Swell Factor
Formula: Bank Volume × 1.25 (for 25% expansion)
Example: 1500 CFT × 1.25 = 1875 CFT of loose soil.
Step 3: Calculate Truck Trips
Formula: Total Loose Volume ÷ Truck Capacity
If using standard Tractor Trolleys (approx. 1 Brass / 100 CFT capacity):
1875 CFT ÷ 100 CFT = 18.75.
Result: You will need to pay for 19 Tractor Trolley trips to remove all the soil.

Pro Tip for Site Management: If you plan to backfill the foundation later, do not haul all the soil away! Estimate how much soil is needed to fill the gaps around your RCC columns, and leave that specific amount of soil on-site.