Brick Calculator
Bricks per square metre, total count and the mortar to lay them.
How it works
The number of bricks per square metre follows from the brick face plus a 10 mm mortar joint. A single brick laid half-brick thick gives about 51 per square metre; a thickened brick gives 39, and a double gives 26 — which is the entire reason larger formats are cheaper to lay.
Multiply by the wall thickness in half-bricks and you have the total. Always subtract openings, always add a waste allowance — 5% is normal for a straight wall and 10% where there are many cuts, corners or a decorative bond. Bricks arrive damaged too, which the allowance is also there to cover.
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How the Brick Calculator works
A brick calculator works out how many bricks a wall of given dimensions needs, accounting for brick format, wall thickness, openings and a breakage allowance. It also returns the masonry volume and the mortar required.
Where 51 bricks per square metre comes from
What is counted is not the brick but the brick plus its 10 mm mortar joint. A standard brick presents a 250 × 65 mm face, which with the joint becomes 260 × 75 mm, or 0.0195 m². Divide one by that and you get 51.3 bricks per square metre of half-brick wall.
The familiar table follows from the same arithmetic: a thickened brick at 88 mm gives 39 per square metre, a double at 138 mm gives 26. This is exactly why larger formats are cheaper to lay — the same wall area takes half as many operations.
Wall thickness and mortar
Thickness is counted in half-bricks. A half-brick wall is 120 mm, one brick is 250 mm, one and a half is 380 mm and two is 510 mm. The per-square-metre figure is multiplied by the number of half-bricks: a standard brick in a one-brick wall already comes to 102 per square metre.
Mortar takes up roughly 23% of finished masonry volume — about 0.23 m³ per cubic metre, and the figure most often forgotten at ordering time. Always subtract window and door openings; on an ordinary house, not doing so over-orders by several thousand bricks.
FAQ
How many bricks per square metre?expand_more
Half-brick thick: 51 standard, 39 thickened, 26 double. In a one-brick wall those double to 102, 78 and 52. All figures already include the 10 mm mortar joint.
What waste allowance should I use?expand_more
Five percent for a straight wall in a simple bond, ten where there are many corners, cuts or a decorative bond. The allowance also covers breakage: part of every pallet arrives with chipped corners, and those bricks are only usable in concealed courses.
How many bricks are on a pallet?expand_more
Typically 275–420 standard bricks depending on stacking and supplier, and around 200–240 thickened. The exact count is always on the delivery paperwork; converting your total into whole pallets before ordering avoids paying for a part load.