Concrete Volume Calculator

Use this calculator to order ready-mix for a rectangular slab, a round pier, or a cardboard form. Pick the shape, enter the sizes that apply, and a price per cubic metre if you have a quote.

A slab is length × width × thickness. A column and a tube (or a round hole) are both a solid cylinder: π × (diameter ÷ 2)² × height. Mass is volume × 2400 kg/m³. Cost is volume × the price you enter. Length, width, height, and diameter can be entered in metres (m) or feet (ft); they are converted to metres before the formula. Mass is shown in kilograms (kg) or pounds (lb). Unused dimensions for the shape you picked can stay at any positive value; only the sizes named for that shape are used.

This is a geometric volume. It does not split out cement bags, rebar, waste, pump loss, or over-excavation. Density is a planning figure, not a mill ticket.

Shape: Slab for a pad; column or tube for a round pier, Sonotube, or hole of the same volume.

Length: Slab length, in m or ft. Unused for a round column or tube.

Width: Slab width, in m or ft. Unused for round shapes.

Height / thickness: Slab thickness or column/tube height, in m or ft. A 100 mm slab is 0.10 m.

Diameter: Column or tube diameter, in m or ft. A 300 mm Sonotube is 0.30 m. Unused for a slab.

Price per m³: Quote per cubic metre of mix. Enter 0 if you only want volume and mass.

Volume (m³): Concrete volume in cubic metres.

Mass: Estimated mass from volume × 2400 kg/m³.

Cost: Volume times the price per cubic metre.