Concrete Calculator

Choose the shape and the concrete grade to get the volume and the materials for the mix.

Volume follows the shape

• Slab: length × width × thickness.
• Strip: total length along the axes × width × height.
• Column: π × (diameter ÷ 2)² × height, multiplied by the number of columns.

Worked example

A 6 × 8 m slab 20 cm thick: 6 × 8 × 0.2 = 9.6 m³. At grade M200 that is roughly 2.5 t of cement, 7 t of sand and 12 t of gravel — two tipper loads. Nobody mixes that volume by hand.

Concrete grades

Why real consumption differs

The proportions are typical, by weight, for dry aggregates. Damp sand adds water to the mix and lowers strength. Different gravel fractions compact differently. For structural work order ready-mixed concrete with a documented strength class instead of mixing by eye on site.

Foundation dimensions come from a design that accounts for the soil and the loads. This calculator works out the volume for dimensions you already have.

🧰Construction Material Calculators

Updated: 2026-09-18