Concrete Calculator
Volume of a slab or footing, and an estimate of pre-mix bags.
A 20 kg bag of pre-mix concrete is taken as about 0.01 m³.
Volume
1.2 m³
20 kg bags
121
Worked example
A slab 4 m by 3 m by 0.1 m is 1.2 m³. At about 0.01 m³ per 20 kg bag of pre-mix, that is 120 bags.
FAQ
- How is the volume calculated?
- Length × width × depth, all in metres.
- How many bags are in a cubic metre?
- This page uses 0.01 m³ per 20 kg bag, so 100 bags per cubic metre, rounded up.
- Is this ready-mix or bagged concrete?
- The volume suits either. The bag count is for pre-mix bags, not for ordering a truck by the cubic metre alone.