Brick Calculator: Bricks per m² and sq ft, With Mortar
How many bricks a wall takes for US modular, UK standard or any brick size, with waste and mortar.
Inputs
- Working
- (19 + 1) cm × (9 + 1) cm = 200 cm² a brick with its mortar; 12 m² ÷ that = 600 bricks, + 5% waste = 630
- Bricks per m²
- 50
- Net wall area
- 12 m²
- Without waste
- 600
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- Two lines of HTML, unlimited views
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What each Brick input means
- Wall length
- The wall's length, in metres or feet.
- Wall height
- The wall's height, in the same unit.
- Doors and windows to leave out
- The total area of doors and windows to take off, in m² or sq ft. A standard door is about 1.9 m² (20 sq ft).
- Brick
- US modular (7⅝ × 2¼ in with ⅜ in joints, BIA's 6.75 per sq ft), UK standard (215 × 65 mm with 10 mm joints, about 60 per m²), or custom for any other brick.
- Brick length
- For a custom brick, its length as laid along the wall, in cm or inches, without the joint.
- Brick height
- For a custom brick, its height in the wall, without the joint.
- Mortar joint
- For a custom brick, the joint thickness: 10 mm is usual in metric brickwork and ⅜ inch in the US.
- Waste allowance
- Extra for breakage and cuts. The Brick Industry Association adds at least 5%, more for walls with a lot of cutting.
- Units
- Metric (metres, m², litres) or US units (feet, square feet, gallons). The wall size, openings and brick dimensions all switch together.
Brick formula
bricks = net wall area ÷ ((brick length + joint) × (brick height + joint)) × (1 + waste %)
The Brick Industry Association calls this the wall-area method: multiply the net wall area — gross area less doors and windows — by the number of brick per square foot or metre. That number comes from one brick's face plus its share of the mortar joint. A US modular brick (7⅝ × 2¼ in, laid with ⅜ in joints) occupies a nominal 8 × 2⅔ in, which is how BIA's Table 4 arrives at 675 brick per 100 sq ft — 6.75 a square foot. A UK standard brick (215 × 65 mm with 10 mm joints) occupies 225 × 75 mm, about 59 a square metre, which builders round to 60. For any other brick, enter its length and height and the joint. BIA then adds at least 5% for breakage and cuts. All of this is for a wall one brick thick (a half-brick or single wythe wall); a cavity wall or double wythe takes two faces' worth.
Brick worked example
A 5 × 2.4 m garden wall in 190 × 90 mm bricks with 10 mm joints: each brick and its mortar covers 20 × 10 cm = 200 cm², or 0.02 m², so 12 m² ÷ 0.02 = 600 bricks, and 630 with BIA's 5% for breakage. The same 129 sq ft wall in US modular brick takes 6.75 a square foot — 872 bricks, 916 with 5% — and BIA's Table 4 puts the mortar at about 7.1 cubic feet before waste.
More Brick examples
A 10 × 2 m garden wall with a 1.5 m² gateway, in UK standard bricks: 18.5 m² net, at 59.3 bricks a square metre is 1,097, and with 5% for breakage 1,152 bricks for one face.
A 20 × 6 ft wall in US modular brick: 120 sq ft × 6.75 = 810 bricks, 851 with 5%, and BIA's Table 4 puts the mortar at 6.6 cu ft before its 15–25% waste allowance.
Where the Brick calculator can give the wrong answer
- One face only. A cavity wall, or a solid wall two bricks thick, takes twice the count — and headers in a Flemish or English bond add more (BIA's Table 6 has the factors).
- Openings are subtracted as entered; the cut bricks around them are what the waste allowance is for.
- Brick names are not sizes. 'Modular', 'Queen' and 'King' differ between manufacturers, so measure the brick or read its spec sheet when you are not using one of the two standard sizes here.
- Mortar is shown only for US modular brick, where BIA publishes it (5.5 cu ft per 100 sq ft with ⅜ in joints); BIA adds 15–25% to the net mortar for waste.
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Brick reference table
| Brick (length × height) and joint | Area each brick covers | Bricks per m² | Bricks per sq ft |
|---|---|---|---|
| US modular, 7⅝ × 2¼ in, ⅜ in joint | 8 × 2⅔ in | 72.7 | 6.75 |
| UK standard, 215 × 65 mm, 10 mm joint | 225 × 75 mm | 59.3 | 5.5 |
| 190 × 90 mm, 10 mm joint | 200 × 100 mm | 50 | 4.6 |
| 230 × 70 mm, 10 mm joint | 240 × 80 mm | 52.1 | 4.8 |
| 230 × 76 mm, 10 mm joint | 240 × 86 mm | 48.4 | 4.5 |
Brick FAQ
- About 60 for UK standard bricks: 215 × 65 mm with 10 mm joints occupies 225 × 75 mm, and 1 ÷ (0.225 × 0.075) = 59.3. A US modular brick is 72.7 a square metre (675 per 100 sq ft).
- 6.75 for US modular brick with ⅜ in joints, according to the Brick Industry Association's Technical Note 10 — 675 per 100 square feet, before waste.
- BIA's general rule is at least 5% on the net brick count, more for walls with a lot of cutting. Mortar is wasted faster: BIA adds 15–25%.
- BIA's Table 4 gives 8.1 cubic feet of mortar per 1,000 modular brick with ⅜ in joints, before waste. Masons' rule of thumb, which BIA calls very rough, is eight bags of masonry cement per 1,000 modular brick.