Excavation Volume Calculator: measuring notes and method
Record depth changes explicitly
Use excavation dimensions, which may differ from the finished slab dimensions. Separate sections with different depths or working-space requirements. This tool treats each entry as a rectangular prism; it does not infer side slopes.
Keep spoil and backfill quantities separate
The result describes in-place geometry. Loose spoil for transport and compacted backfill are different material conditions. Do not use the same volume unchanged for all three without checking the relevant conversion.
Formula
Volume = length × width × depth × quantity. Order volume = volume × (1 + waste ÷ 100).
Worked examples in metric and imperial units
Illustrative values match Reset example and stay fixed when you edit the calculator. Both columns describe the same calculation; converted inputs are rounded.
Metric worked example
- Length
- 6 m
- Width
- 4 m
- Depth / thickness
- 500 mm
- Quantity
- 1
- Waste allowance
- 10 %
Excavated volume with allowance: 13.2 m³
Imperial worked example
- Length
- 19.685 ft
- Width
- 13.1234 ft
- Depth / thickness
- 19.685 in
- Quantity
- 1
- Waste allowance
- 10 %
Excavated volume with allowance: 17.2649 yd³
Follow the calculation
Lengths in this working are in metres.
- Measured volume = 6 × 4 × 0.5 × 1 = 12 m³.
- Allowance multiplier = 1 + 10 ÷ 100 = 1.1.
- Volume with allowance = 12 × 1.1 m³.
Excavation volume versus loose spoil
A 6 m × 4 m × 0.5 m dig contains 12 m³ in place. An illustrative 20% swell produces 14.4 m³ of loose spoil. In the truckload calculator, enter the 12 m³ in-place quantity with 20% swell, rather than applying swell again to 14.4 m³.
Unit conversions
1 m³ = 1,000 L ≈ 1.30795 yd³. One cubic yard is 27 ft³.
Reviewed 19 October 2026. How calculations are checked · Report a correction