Brick & Block Calculator

How many bricks per square metre?

UK bricklayers work to a standard of 60 bricks per square metre for a half-brick (single-skin) wall built with standard 215 × 102.5 × 65mm bricks and a 10mm mortar joint. A one-brick (double-skin) wall is simply two of those skins, so it takes 120 bricks per square metre. Multiply your wall area by the right figure, add a wastage allowance for breakages and cuts, and you have your order — which is exactly what this calculator does, rounding up so you're never left short.

How many blocks per square metre?

A standard UK concrete block measures 440 × 215mm on its face, and with a 10mm mortar joint that works out at almost exactly 10 blocks per square metre. Blocks cover ground far faster than bricks, which is why inner skins, partitions and garage walls are usually built from them. For a cavity wall you need both: roughly 60 bricks per m² for the outer skin and 10 blocks per m² for the inner skin, which this tool totals separately.

How much mortar do I need for bricklaying?

As a rough guide, a half-brick wall uses about 0.022 m³ of mortar per square metre, and a double skin uses about twice that; blockwork uses roughly half a brick skin because the joints are fewer and further apart. This calculator estimates the mortar volume for your wall type, then splits it into a 4:1 sand-to-cement mix by volume — assuming building sand at about 1.6 tonnes per m³ and cement supplied in 25kg bags — so you get a sand tonnage and a bag count. Treat it as an ordering guide, not a lab figure: joint thickness and how carefully the mix is buttered make a real difference on site.

What about footings and finishing?

Every new wall needs a footing underneath it — our Concrete Calculator works out the volume and materials for a strip footing before you lay the first course. Once the wall's up, rendering or skimming it needs its own materials — see our Plaster & Render Calculator for bags of render, bonding or skim.

Does this tool store my details?

No. There's no sign-up and nothing to submit — every calculation runs entirely in your browser as you type. Nothing you enter is uploaded, saved or sent anywhere, so you can use it as many times as you like without leaving a trace.