Basic concept
Start with excavation volume and subtract the volume occupied by permanent or retained work, according to the estimating method.
Worked example
If excavation is 50 m³ and an assumed 20% is occupied by structure, a simple preliminary backfill estimate is 50 × 0.80 = 40 m³.
How to use the calculator
Enter excavation volume and the excluded/occupied percentage requested by the calculator.
Earthwork considerations
Compaction, bulking, shrinkage, soil suitability, imported fill and disposal can change actual material movement.
Who uses it
Site engineers, contractors, quantity surveyors and estimators.
Use the Backfill Calculator
Enter your project values and get a quick preliminary calculation.
Frequently Asked Questions
Is backfill equal to excavation?
Not always.
Does it include compaction?
A simple volume estimate does not represent every compaction effect.
Can excavated soil always be reused?
No; soil suitability and specifications control reuse.
Who uses this tool?
Site teams, contractors, surveyors and students.