KNOW THE MATH
How it works
Use this estimator for rectangular slabs with a uniform thickness. Uneven ground, trenches, footings and reinforcement details can affect actual concrete requirements. Order quantities should be confirmed with your supplier.
Formula
Concrete (m³) = length (m) × width (m) × thickness (m) × (1 + waste percentage).
Worked example
A 5 × 4 m slab that is 15 cm thick needs 3 m³ before waste; with 5% allowance, 3.15 m³.