Work out trench volume instantly with clear inputs, formula shown and shareable results.
Trench excavation is a simple prism of length, width and depth. Within it, the bedding layer beneath the pipe is a separate imported material, and the remainder is backfill. Spoil is shown at 25 percent bulking because that is the volume actually needing space alongside the trench or on a lorry.
Excavation
V = length x width x depth
Split
Bedding = length x width x bedding thickness; backfill = excavation - bedding
V = length x width x depth. Trench excavation is a simple prism of length, width and depth.
For a large diameter pipe, yes. For small services the pipe displaces so little that ignoring it is well inside the accuracy of the trench dimensions.
This calculator takes 4 inputs: Trench length, Trench width, Trench depth, Bedding thickness. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.