Brick & Block Calculator
How many bricks or blocks a wall takes, and how much mortar — counted by the course module with the joint included, the way a mason quotes. The handbook figure of 51.3 standard bricks per m² per half-brick wythe falls straight out of the arithmetic.
The module does the counting
Masonry maths reduces to one idea: the wall's face is a grid of modules, each one unit plus one joint in both directions. Divide the net face area by the module's area and you have the units per wythe; multiply by the wythes of the wall's thickness and add breakage — rounded once, at the end, into whole pieces.
Mortar is what fills everything that is not brick: face joints, bed joints and the collar between wythes, which is why the honest way to get it is volumetric — wall volume minus brick volume — rather than a per-thousand rule of thumb that silently assumes one joint size.
Frequently asked questions
Why is the joint part of the count?
Because a course is a module: brick plus joint. A 250 mm brick with a 10 mm joint occupies 260 mm of the wall, so a square metre holds 1/(0.26 × 0.075) = 51.3 of them per wythe — not the 61.5 you get by dividing by the bare brick face. Forgetting the joint over-orders by a fifth.
What is a wythe?
One vertical layer of units — yarım kərpic in the trade. A 120 mm wall is one wythe of standard brick, 250 mm is two, 380 mm three, 510 mm four. Blocks are usually laid single-wythe, which is why a block wall divides by nothing.
Where does the mortar number come from?
From subtraction: the wall's volume minus the volume of the units themselves, using the unrounded count — the mixer does not care about the waste pile. For standard brick it lands near 0,2 m³ per 10 m² per wythe; for glued AAC blocks it is close to nothing, which is the point of glue.
How much breakage should I allow?
Five per cent for brick handled normally, more if it travels far or the wall has many cuts; two to three per cent for blocks, which cut cleanly. The waste is applied to the count before rounding, so it never buys a phantom pallet.
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