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Block Calculator

How many blocks do I need?

Enter your walls and we count the blocks. Then send the number to us for a quote.
Add up every wall you are building.
A door is about 2 m², a window about 1.5 m².

You need about

0

6″ Hollow Blocks

Wall area
0.0
Less doors & windows
0.0
Blocks per m²
9.25

Free delivery to site. An estimate for 450 × 225 mm blocks with 10 mm joints — your builder’s or quantity surveyor’s figures take priority.

The method

How the count works

A standard block has a 450 × 225 mm face. With a 10 mm mortar joint on each side, one block covers 0.46 × 0.235 m — about 0.108 m² — so a square metre of wall takes about 9.25 blocks. Hollow and solid blocks, and the 6, 5 and 4 inch sizes, all share that face, so the count is the same for each.

Example: a wall 10 m long and 3 m high is 30 m². 30 × 9.25 = 278 blocks, and with 5% allowed for breakage and cutting, about 292 blocks.

Take the doors and windows out of the area first — a door is roughly 2 m² and a window about 1.5 m². Not sure which size to use? Our FAQ explains which block goes where, or ask us.

Request a Quote

Tell us what you are building.

Send the blocks, the quantity and the place. We reply on WhatsApp with a price.