Concrete Calculator
Calculate concrete volume, bags needed, and cost for your construction project. Perfect for driveways, slabs, footings, and concrete work.
Concrete Calculator
Concrete Results
Enter dimensions to calculate concrete
About the Concrete Calculator
Our free concrete calculator estimates the volume of concrete needed for slabs, footings, columns, and other shapes. Enter dimensions in metres or feet and get cubic metres, cubic yards, and the number of 20 kg or 25 kg bags. Use it for driveways, foundations, and footpaths. Always order a little extra for waste. For area of the slab first, use our area calculator.
You may also find our area calculator and volume calculator useful.
Frequently Asked Questions
How much concrete do I need for a slab?
Multiply length × width × depth (in the same units) to get volume. This calculator does that for common shapes and converts to bags and cubic yards.
How many bags of concrete per cubic metre?
It depends on bag size. A 20 kg bag makes about 0.01 m³; a 25 kg bag about 0.013 m³. The calculator shows the approximate number of bags for your volume.
Do I need to add extra for waste?
Yes. Order about 5–10% extra to allow for spillage, uneven subgrade, and formwork. Round up when buying bags.