Method
How this tool works
Volume = length × width × depth. Order volume = volume × (1 + waste percentage). Bags round up from stated bag yield.
Worked example
A 2 m × 2 m × 0.1 m slab is 0.4 m³ before waste.
Volume, waste & bags
Concrete Calculator
Calculate concrete volume for a rectangular slab and add a practical waste allowance and bag estimate.
Use responsibly
Assumptions & limitations
Ground variation, reinforcement displacement and supplier minimums can change the order. Confirm bag yield on the manufacturer label.
Last reviewed: 20 July 2026
Calculation and copy checked for this release.