Excavation and Spoil Removal Calculator

Soil in the ground is compacted. Once dug, it loosens and occupies more volume — that increase is called bulking or swell. A dig that measures 20 m³ in situ can easily become 24 m³ of loose spoil to tip away if bulking is 20%. Always plan haulage and skips on the loose volume.

It depends on the ground. As a rough UK guide: sand and gravel often bulk around 10–15%, mixed ground around 20%, topsoil around 25%, clay around 25–40%, and chalk can be 30–40% or more. Site investigation and past tip tickets are better than generic figures, this calculator lets you override the default for any soil type.

For trenches, pits, foundations and basement digs use length × width × depth (in metres) for in-situ volume in m³. For circular pits use π × (diameter ÷ 2)² × depth. Multiply by quantity when you have several identical pits.

Divide the loose spoil volume by the usable capacity of your skip or tipper, then round up. A 6 m³ skip rarely takes a full 6 m³ of wet clay, so enter the capacity you actually achieve on site.

Enter a price per cubic metre of loose spoil, or a price per load. If both are given, price per m³ is used for disposal. Optionally add a price per tip journey for haulage. Figures are estimates only and exclude permits, waiting time, contaminated spoil surcharges and VAT unless those are already in your rates.

Each filled skip or tipper load usually needs one tip journey. If you have more than one vehicle, the calculator also shows journeys per vehicle so you can plan the day.