Concrete calculator
Enter the size of your slab, column, beam or footing to get the concrete volume and the bags of cement, sand and granite for a 1:2:4 or other mix.
Free, no sign-upRuns in your browser
Change the assumptions
You need
Cement0 bags50 kg bags
Concrete volume0 m³wet volume
Sharp sand0 t0 m³
Granite0 t0 m³
Water0 Lat 25 L per bag
Dry materials = wet volume × 1.54. Sand is about 1.6 tonnes per m³ and granite about 1.5 tonnes per m³.
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What does 1:2:4 mean?
One part cement, two parts sand and four parts granite by volume. It is the usual mix for slabs, beams and columns in houses.
How much water does concrete need?
About 25 litres for each 50 kg bag of cement (a water–cement ratio of 0.5).
Is it free?
Yes. This tool is free to use, with no sign-up.
Is what I type stored?
No. Everything happens in your browser and nothing is sent to our servers.
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