How to Calculate Excavation Quantity for Foundation

By Vystra · 27 August 2026

Excavation is the first billable activity on site, so getting the quantity right sets the tone for the whole estimate. Here's the clean method.

The formula

Excavation volume = Length × Width × Depth, summed across all footings and trenches.

Worked example

For 8 isolated footings, each 1.5 m × 1.5 m × 1.5 m deep:

• Per footing = 1.5 × 1.5 × 1.5 = 3.375 m³
• Total = 3.375 × 8 = 27 m³

Add trench excavation for plinth beams separately.

What changes the price

• Soil type — hard/rocky soil costs more than soft soil.
• Depth — deeper pits need shoring and cost more.
• Manual vs machine — JCB is faster for large volumes; manual for tight sites.
• Disposal — carting excess soil away is a separate cost.

Track it against the project

Excavation over-runs quietly when soil is harder than expected. Logging the actual quantity and cost against the project keeps your foundation-stage budget honest. Vystra tracks every stage cost per project, so excavation over-runs show up before they eat the next stage's budget.

Frequently asked questions

How do you calculate excavation quantity?

Excavation volume = length × width × depth of the pit or trench. Add up all footings, then convert to cubic metres or cubic feet.

How is excavation cost calculated in India?

Excavation is usually priced per cubic metre or per cubic foot. Rates depend on soil type, depth and whether the work is manual or machine.

What is the unit for excavation work?

Excavation is measured in cubic metres (m³) or cubic feet (cft) of soil removed.