Trench Volume & Backfill Estimation
Trenching for utility lines, drainage, or foundations requires precise calculations to balance material hauling. Our Trench Calculator goes beyond simple volume by accounting for the space taken up by the pipe and the imported bedding material, giving you the "Net Backfill" number—the actual amount of soil you can put back into the hole. If you are calculating general dirt removal for basements or pools, our Excavation Calculator might be more appropriate.
This is essential for determining how much soil must be hauled off-site (spoil) versus how much can be reused.
Trench Cross-Section
The calculator assumes bedding is placed across the full width of the trench bottom.
Formulas
- Total Excavation: Length × Width × Depth
- Bedding Volume: Length × Width × Bedding Depth
- Pipe Displacement: π × (Radius)² × Length
- Net Backfill: Total Excavation - (Bedding + Pipe)
Safety Warning: Trenches deeper than 5 feet require protective systems (sloping, shoring, or shielding). Please consult official OSHA Trenching Standards before digging. This calculator computes straight-wall volume only.