Excavation volume calculator

Every mode reduces the excavation to a plan area and a depth, works in cubic feet, and converts once at the end. One cubic yard is exactly 27 cubic feet, and one acre is exactly 43,560 square feet — those are definitions, not approximations, so no rounding enters before the result.

Rectangular

volume = length × width × depth

Each dimension converts from its own unit first, so 18 in of depth and 1.5 ft of depth give the same answer.

Area + depth

volume = area × depth

For a footprint you have already taken off. Assumes the depth is uniform across the whole area.

Trench

volume = ((bottom width + top width) ÷ 2) × depth × length

A trapezoidal section. Leave top width blank for vertical walls and it collapses to bottom width × depth × length.

Loose volume

loose = bank × (1 + swell%)

Only calculated once you give a swell factor for the material you are digging.

Truck loads

loads = ⌈loose ÷ truck capacity⌉

Rounded up, because a partial load still sends a truck. If you also give a density and a legal payload, the weight limit is checked and the binding constraint wins.