Excavation Calculator
Estimate excavation volume, soil swell, truck loads, and cost for pads, trenches, and custom areas in both metric and imperial units.
Swell factor converts in-situ volume to loose volume for haul-off or stockpiles.
yd³ per load
per yd³ of loose material
ft
ft
ft
identical pads
Excavation areas
| # | Type | Dimensions | In-situ volume | Loose volume | Remove |
|---|---|---|---|---|---|
| No areas added yet. Enter dimensions above and click “Add to list”. | |||||
Results
Volume summary
- Total in-situ volume
- 0.00 yd³
- Total loose volume (after swell)
- 0.00 yd³
- Equivalent compacted backfill
- 0.00 yd³
Compacted backfill assumes the same swell factor in reverse (loose ÷ swell).
Trucking & cost
- Estimated truck loads
- –
- Estimated cost
- –
Enter truck capacity and cost per unit above to see trucking and cost estimates.
How this excavation calculator works
This excavation calculator is designed for contractors, estimators, and DIY builders who need fast, transparent volume and cost estimates. It supports multiple excavation types (pads, trenches, and custom areas), both imperial and metric units, and soil swell factors.
1. Volume formulas
Rectangular pad / footing:
\( V = L \times W \times D \)
Trench:
\( V = L \times W \times D \)
Custom area:
\( V = A \times D \)
where L = length, W = width, D = depth, A = plan area.
All volumes are first calculated in the base unit (ft³ or m³), then converted to cubic yards or cubic meters for reporting.
2. Swell (bulking) factor
When soil is excavated, it breaks apart and occupies more space. This is called swell or bulking. The calculator uses a swell factor to convert in-situ volume to loose volume:
\( V_{\text{loose}} = V_{\text{in-situ}} \times \text{swell factor} \)
Example: 100 yd³ of in-situ clay with a swell factor of 1.30 becomes 130 yd³ of loose material.
3. Truck loads and cost
Once loose volume is known, truck loads and cost are straightforward:
Truck loads:
\( \text{Loads} = \dfrac{V_{\text{loose}}}{\text{truck capacity}} \)
Cost estimate:
\( \text{Cost} = V_{\text{loose}} \times \text{cost per unit} \)
Typical swell factors by material
| Material | Typical swell factor | Approx. swell (%) |
|---|---|---|
| Loose sand | 1.15 – 1.25 | 15 – 25% |
| Sandy clay | 1.20 – 1.30 | 20 – 30% |
| Clay | 1.25 – 1.35 | 25 – 35% |
| Gravel / broken rock | 1.30 – 1.50 | 30 – 50% |
Values are typical ranges. Always confirm with geotechnical data or your local experience when bidding projects.
Limitations and good practice
- This tool assumes uniform depth and soil conditions within each area.
- It does not account for side slopes, over-excavation, or compaction effort.
- For critical projects, use this as a preliminary estimate and refine with detailed plans and geotechnical reports.
FAQ
How accurate is this excavation calculator?
For simple pads and trenches with uniform depth, the calculator is mathematically exact. Real-world quantities can differ due to sloped sides, over-digging, obstructions, and varying soil conditions. Many contractors add a contingency (e.g., 5–15%) on top of the calculated volume.
Should I use in-situ or loose volume for pricing?
It depends on how your subcontractors quote. Excavation contractors often price per in-situ cubic yard or cubic meter, while trucking and disposal are usually priced per loose volume. This tool shows both so you can match your vendors’ units.
Can I use this for backfill and imported material?
Yes. Use the compacted backfill volume as a starting point, then apply a compaction factor or density for your specific material. For example, granular base or structural fill may require more loose material to achieve the compacted volume.
Does this handle multiple excavation phases?
You can group areas by phase (e.g., “Building A pad”, “Utility trenches”, “Retaining wall footings”) and add them separately. Export or note the results for each group before clearing the list and starting the next phase.