Concrete Trench Volume Calculator
This calculator estimates the concrete required to fill rectangular trenches. Enter trench dimensions in metres, set the number of identical trenches, and include an allowance for waste. Outputs include volume in cubic metres, cubic yards, and cubic feet, an estimated mass using standard concrete density, and an estimate of ready-mix truck loads.
The tool assumes rectangular cross-sections. For trapezoidal or v-shaped trenches, use the average width across the depth or consult an engineer for precise excavation shapes. Values are approximate; final ordering should be confirmed with site measurements and supplier guidance.
Inputs
Results
Required concrete volume (m³)
0.99
Required concrete volume (yd³)
1.2949
Required concrete volume (ft³)
34.9615
Estimated concrete mass (kg)
2,376
Ready-mix trucks required
0.1238
| Output | Value | Unit |
|---|---|---|
| Required concrete volume (m³) | 0.99 | m³ |
| Required concrete volume (yd³) | 1.2949 | yd³ |
| Required concrete volume (ft³) | 34.9615 | ft³ |
| Estimated concrete mass (kg) | 2,376 | kg |
| Ready-mix trucks required | 0.1238 | — |
Visualization
Methodology
Primary volume is computed with the standard prismatic formula: length × width × depth per trench, multiplied by the number of trenches and increased by the user-specified waste allowance.
Conversions use standard SI relationships: 1 m³ = 1.30795062 yd³ and 1 m³ = 35.3146667 ft³. Estimated mass uses a nominal concrete density of 2400 kg/m³ (typical for normal-weight concrete).
Ready-mix truck counts are an estimate dividing required volume by the user-supplied typical truck capacity (m³). Round up physical orders to account for staging, return, and minimum dispatch sizes when placing an order with a supplier.
Further resources
External guidance
Expert Q&A
Can I use this calculator with imperial measurements (feet/inches)?
This calculator accepts metres for dimensions. To use feet, convert values to metres first (1 ft = 0.3048 m). For convenience, multiply feet measurements by 0.3048 before entering them.
What waste allowance should I use?
A common practice is 5–10% for straightforward pours and 10–15% for complex sites or deeper trenches. Increase allowance for inaccurate site dimensions, spillage, or extended pumping lines.
Why does the tool use 2400 kg/m³ for mass estimates?
2400 kg/m³ is a commonly used nominal density for normal-weight concrete used in many engineering references. Actual density varies with mix design and aggregates; use supplier data for precise mass calculations.
Does the calculator consider reinforcement (rebar) displacement?
No. Reinforcement typically displaces a small concrete volume; for heavy reinforcement or close tolerances, subtract the estimated rebar volume or consult a structural engineer for precise ordering.
Are there safety or regulatory considerations for trenches?
Yes. Trenching and excavation carry hazards including collapse, confined spaces, and utility strikes. Follow local regulations and guidance such as occupational safety authorities' trenching and excavation standards before working in trenches.
Sources & citations
- NIST — SI units and unit conversions — https://www.nist.gov/pml/weights-and-measures/si-units
- OSHA — Trenching and Excavation Safety — https://www.osha.gov/trenching-excavation
- MIT Concrete Sustainability Hub — research and reference — https://cshub.mit.edu
- Whole Building Design Guide — Concrete materials guidance — https://www.wbdg.org/materials-products/construction-materials/concrete