Block calculator
Enter your wall length and height to see how many 6-inch or 9-inch blocks you need, with extra for breakage, and the cement and sand to lay them.
Change the assumptions
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How many blocks make one square metre?
A standard 450 × 225 mm block with 10 mm mortar joints covers about 0.108 m², so about 9 to 10 blocks make one square metre of wall.
How many blocks can one bag of cement lay?
Builders usually get 30 to 40 nine-inch blocks, or 40 to 50 six-inch blocks, from one 50 kg bag. You can change this in the calculator.
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.
