Enter the length, width and thickness of the slab.
Formula
Volume = length × width × thickness
Worked example
A 4 × 3 m slab, 10 cm thick, needs 1.2 m³ of concrete.
Frequently asked questions
How thick should a slab be?
Often 10 to 12 cm for a path or shed base, more for a driveway; follow local building advice.
When should I order ready-mixed concrete?
Above about 1 m³, a truck delivery is usually easier than bags.
How many bags per m³?
About 2,200 kg of dry mix per m³, so around 88 bags of 25 kg.
Related calculators
- Paint Calculator: How Much Paint Do I Need?
- Tile Calculator: How Many Tiles Do I Need?
- Flooring Calculator: Laminate and Wood Packs
- Wallpaper Calculator: How Many Rolls?
- Gravel, Sand and Topsoil Calculator
- All calculators in this category
Results are estimates for information only. Check important figures with a professional.