About this calculator
Ordering concrete means knowing your volume precisely — order short and the pour fails, order long and you pay for waste. This calculator turns a slab or footing’s dimensions into volume in cubic metres, feet and yards, and estimates how many ready-mix bags you would need.
How it works
Volume is length × width × depth for one section, multiplied by the number of identical sections. Depth is entered in centimetres (metric) or inches (imperial) and converted automatically, then the result is expressed in cubic metres, cubic feet and cubic yards.
Frequently asked questions
What shape does this assume?
A rectangular slab or footing of uniform depth. For steps or irregular shapes, split them into rectangles and add the results.
How many bags will I need?
The estimate divides total volume by a standard 80 lb (36 kg) bag yield of about 0.6 ft³ and rounds up. Buy a little extra for spillage.
Metric or imperial?
Both. Metric uses metres and centimetres; imperial uses feet and inches.
Does it include reinforcement?
No — it covers concrete volume only, not rebar, mesh or formwork.