How the brick count is worked out
Each brick plus its joint occupies a rectangle on the face of the wall: the brick length plus the joint, multiplied by the brick height plus the joint. One square metre divided by that rectangle gives the number of bricks per square metre.
A standard UK brick is 215 mm long and 65 mm high, and a 10 mm joint makes the module 225 mm by 75 mm. One square metre divided by 0.016875 is 59.26 bricks, which is the trade figure of 60.
The net wall area is the length multiplied by the height, less the area of any openings. The waste allowance is added after that, as a percentage.
Worked example
A wall 6 metres long and 2.4 metres high is 14.4 square metres. At 59.26 bricks per square metre that is 853 bricks, and adding 5 per cent for cutting and breakage gives 896 bricks.
The same wall with a 2 square metre window would be 12.4 square metres, which is 735 bricks before waste.
Single skin, cavity and piers
The figure is for a single leaf of brickwork, which is what a garden wall or a brick skin over blockwork uses. A solid 215 mm wall or a cavity wall has two leaves, so it needs twice the bricks.
Piers, chimneys and anything that projects need their own measurement. Add them as extra wall area rather than guessing a percentage.
The bond pattern changes the appearance, not the count. Stretcher, English and Flemish bond all use about the same number of bricks per square metre, because the wall area is the same.
Limits of this calculator
It counts bricks. It does not count blocks, mortar, wall ties, insulation, lintels or damp course, and it does not design the wall.
It assumes a running bond with a consistent joint. A ring, a curved wall or a decorative pattern with a lot of cutting needs a higher waste allowance than 5 per cent.
It does not check whether the wall needs piers, movement joints or a structural engineer, which depend on height, exposure and what the wall carries.
For US brick sizes and square feet, use the US brick calculator.
Inputs for the brick calculator
Wall length
The full run of the wall in metres, ignoring openings at this stage.
Wall height
From the damp course to the top of the wall in metres.
Doors and windows
Total area to leave out, in square metres. Enter zero for a solid wall.
Brick length
Face length in millimetres. A standard UK brick is 215 mm.
Brick height
Face height in millimetres. A standard UK brick is 65 mm.
Mortar joint
Joint thickness in millimetres, usually 10 mm.
Waste allowance
Extra for cutting and breakage. Five per cent is normal, more for a heavily cut wall.
CALCULATOR QUESTIONS
UK brick calculator questions
How many bricks are in a square metre?
About 60 for a standard 215 x 65 mm brick with a 10 mm joint, in a single leaf.
Does a cavity wall need twice as many?
Yes. Two leaves means two skins, so double the count, and the inner leaf is often blockwork instead.
What about a different brick size?
Enter its real length and height. The count follows the size you enter, so an imperial or a reclaimed brick still works.
Should I add more than 5 per cent waste?
For a plain wall, 5 per cent is enough. Add 10 per cent for lots of cutting, a curved wall or a decorative bond.