Brick and block sizes
9 masonry units with their actual size, their working format, and how many of each a square metre takes.
Sixty bricks to the metre, and where that comes from
A British brick is 215 × 65 mm on the face, and that pair of numbers is not what a wall is built from. Add one 10 mm joint and the working unit — the format size — is 225 × 75. From there:
1,000,000 mm² ÷ (225 × 75) = 59.26 bricks per m²That is the trade figure of sixty, and it is arithmetic rather than folklore. Ten courses rise exactly 750 mm, which is why brick buildings have so many dimensions that are multiples of 75.
Why a block is three brick courses
A British block is 440 × 215 mm, so its format is 450 × 225 — and 225 is exactly three brick courses of 75. That is deliberate. A cavity wall has brick on the outside and block on the inside, and they have to arrive level at every tie: one block course, three brick courses.
What "modular" means in an American brick
Modular is a relationship rather than a size: the unit plus its joint is meant to land on an eight-inch grid so a whole building can be set out on one. In length it does exactly that — 7 5/8 inches plus a ⅜ inch joint is 8, to the thousandth.
In height it does not, and most charts skip this. 2 1/4 plus ⅜ is 2⅝, so three courses come to 7⅞ inches, not 8. The missing eighth is made up on site by running the bed joint a little fuller than the perpend — about 7/16 rather than ⅜. So the eight-inch module is real, and half of it is achieved by the bricklayer rather than by the brick.
Queen and king bricks are taller and thinner, which means fewer units and less labour for the same wall. They also do not course with modular brick, so the choice is made once for a building rather than per delivery.
Every unit
| Unit | Region | Actual (mm) | Format | Per m² | Courses/m |
|---|---|---|---|---|---|
| UK standard brick | United Kingdom | 215 × 65 × 103 | 225.0 × 75.0 | 59.3 | 13.3 |
| UK imperial brick | United Kingdom | 228 × 68 × 108 | 238.0 × 78.0 | 53.9 | 12.8 |
| UK metric modular | United Kingdom | 200 × 75 × 100 | 210.0 × 85.0 | 56.0 | 11.8 |
| UK concrete block | United Kingdom | 440 × 215 × 100 | 450.0 × 225.0 | 9.9 | 4.4 |
| US modular brick | North America | 194 × 57 × 92 | 203.2 × 66.7 | 73.8 | 15.0 |
| US queen brick | North America | 194 × 70 × 79 | 203.2 × 79.4 | 62.0 | 12.6 |
| US king brick | North America | 244 × 70 × 76 | 254.0 × 79.4 | 49.6 | 12.6 |
| US utility brick | North America | 295 × 92 × 92 | 304.8 × 101.6 | 32.3 | 9.8 |
| US concrete block | North America | 397 × 194 × 194 | 406.4 × 203.2 | 12.1 | 4.9 |
Ordering
The per-square-metre figures above are for a single skin and assume no waste. Add five per cent for breakage and cutting on a plain wall, and ten on anything with a lot of openings or angles — corners and reveals generate cut bricks that cannot be reused elsewhere.
A double-skin wall is two of these figures, not one, and a cavity wall of brick and block is one of each. The commonest ordering mistake is counting the wall once.