Excavation Calculator
Estimate a rectangular excavation and compare in-situ and loose spoil volume.
Planning more than one room or material? Build a project shopping list →
How to use it
- Replace the examples with your measurements or exact product coverage.
- Choose the unit beside each input. Changing the unit converts the existing value.
- Choose any allowance deliberately, calculate, and check the purchase units.
Formula
In-situ volume = L × W × depth. Loose volume = in-situ volume × (1 + entered bulking/100).
Worked example
5 × 4 × 0.1 m = 2 m³ in situ; 10% bulking gives 2.2 m³ loose.
Common mistakes and limits
The allowance field represents bulking here. No trench support, slopes, utilities, haulage weight or soil safety design.
Do not add allowance twice. Example coverage, density and prices are illustrative, not a specification for your project.
Frequently asked questions
What does the bulking percentage mean?
It models how loose spoil volume differs from the measured in-situ volume. Choose a value from project-specific advice.
Does the result determine the number of skips?
No. Usable capacity, weight limits and material acceptance must be checked with the provider.
Are my measurements sent to a server?
These calculations run in your browser. This calculator does not send the input values to our server. Normal page requests can still appear in hosting logs.
Measurement guides
Related calculators
Browse the tools below.