Concrete Calculator
Estimate concrete volume for slabs, footings and columns, plus how many concrete bags or cubic yards you need for your pour.
Concrete Volume & Bag Estimator
How concrete volume is calculated and ordered
Concrete volume is determined from the dimensions of the space to fill. For a rectangular slab, multiply length by width by thickness after converting all measurements to the same unit. A 4 m by 3 m slab that is 0.1 m thick contains 1.2 m³ before any order allowance. A footing, column, or irregular foundation requires its own geometry; combining dimensions from different units without converting them first produces misleading volumes.
Ordered concrete is often greater than the theoretical shape volume because excavation irregularities, uneven subgrade, overbreak, spillage, and placement can add demand. An allowance should follow the actual construction conditions rather than being treated as a universal percentage. If concrete is sold in cubic yards and the calculations are in cubic metres, convert the final volume once before requesting supplier pricing to avoid double conversion.
Concrete volume does not determine an appropriate strength grade, reinforcement schedule, curing approach, or safe slab thickness. Those depend on loads, soil, climate, design codes, and the mix design. Confirm minimum order quantities, delivery access, and whether any volume loss is included in the supplier quote before scheduling a pour.