TAHA Engineering Toolsby TAHA Knowledge Lab

Civil & Construction

Excavation Volume Calculator

In-place volume of pits and trenches, plus optional loose (bulked) volume.

Inputs

Calculate from
Rectangular pit dug below the ground surface with length L, width W and depth D.existing groundLWD
Rectangular pit with vertical sides: length L, width W and depth D below existing ground. In-place volume = L × W × D. Diagram not to scale.

Average depth below existing ground level.

Optional. Excavated soil takes up more space when loose. Only enter a value you have from soil data or experience; leave empty to skip.

Result

In-place (bank) volume
18
Volume of one excavation
9
Plan area of one excavation
6

The ground to be removed is 18 m³ in place.

  • Vertical sides are assumed. Sloped or stepped sides, working space and over-dig add volume.

Educational estimate — check the assumptions below.

About this calculator

Work out how much soil must be dug out of a pit, trench or circular pit. The main result is the in-place (bank) volume: the volume of the hole. Soil expands when dug out, so if you enter a bulking (swell) percentage the calculator also gives the loose volume, which is what you need for haulage and spoil storage.

Formula

Rectangular pit

V = L × W × D × n

Loose volume = V × (1 + bulking)

Trench

V = length × width × D × n

Loose volume = V × (1 + bulking)

Circular pit

V = π × d² ÷ 4 × D × n

Loose volume = V × (1 + bulking)

Worked example

  • Pits: 2 × (3 m × 2 m × 1.5 m) = 18.0 m³ in place. With 25% bulking: 18.0 × 1.25 = 22.5 m³ loose.
  • Trench: 25 m × 0.6 m × 1.2 m = 18.0 m³.
  • Circular pit: Ø1.2 m × 2 m deep = π × 1.2² ÷ 4 × 2 = 2.26 m³.
  • Imperial trench: 10 ft × 3 ft × 4 ft = 120 ft³ = 4.44 yd³.

Assumptions and limitations

  • Vertical sides and a flat bottom at the depth entered. Sloped or benched sides, working space around foundations and uneven ground need extra volume.
  • Bulking depends strongly on the soil type and moisture. The calculator never applies a bulking value unless you enter one.
  • In-place volume is the hole; loose volume is the dug soil; compacted fill may be smaller again. Keep these separate when planning.

Safety note

This calculator does not check trench or pit stability. Excavations can collapse without warning. Follow your local regulations for sloping, shoring, edge protection and safe access, and get competent advice for deep excavations or poor ground.

References

  • Volume formulas for rectangular prisms and cylinders; in-place vs loose volume as used in earthwork estimating.