Trench volume Calculator: measuring notes and method
Measure clear trench lengths
At trench intersections, count the shared excavation once. Enter excavation depth rather than pipe diameter or bedding depth.
Reconcile excavation with what stays in the trench
Backfill is not automatically equal to the excavated volume. Deduct permanent pipes, concrete and separately specified bedding from the trench geometry, then account for the supplied material condition separately.
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
- Trench length
- 20 m
- Trench width
- 0.4 m
- Trench depth
- 600 mm
- Quantity
- 1
- Waste allowance
- 0 %
Trench volume: 4.8 m³
Imperial worked example
- Trench length
- 65.6168 ft
- Trench width
- 1.3123 ft
- Trench depth
- 23.622 in
- Quantity
- 1
- Waste allowance
- 0 %
Trench volume: 6.2782 yd³
Follow the calculation
Lengths in this working are in metres.
- Measured volume = 20 × 0.4 × 0.6 × 1 = 4.8 m³.
- Allowance multiplier = 1 + 0 ÷ 100 = 1.
- Volume with allowance = 4.8 × 1 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