Each brick takes up its own face plus one mortar joint along the top and one at the end. So the number per square meter or square foot is 1 ÷ ((length + joint) × (height + joint)), and the wall needs that many times its area, less the doors and windows, plus a few for breakage.
Example: a garden wall 30 ft long and 8 ft high with a 20 ft² gate opening has 220 ft² of face. US modular bricks with 3/8 in joints: 8 × 2.625 in = 21 in² each, so 6.86 per ft². 220 × 6.86 = 1,509, plus 5% = 1,585 bricks for one leaf. The same wall in UK bricks takes 1,272 with the same 5%, because the UK brick is longer and taller.
Bricks and blocks per area
One leaf (wythe), with the usual joint. “Mortar” is the volume of the bed and head joints only.
| Unit | Joint | Per m² | Per ft² | m² per 1,000 | Mortar in the joints |
|---|---|---|---|---|---|
| US modular brick, 7 5/8 × 2 1/4 × 3 5/8 in | 3/8 in | 73.8 | 6.86 | 13.5 | 17 L per m² |
| UK / Irish brick, 215 × 65 × 102.5 mm | 10 mm | 59.3 | 5.51 | 16.9 | 18 L per m² |
| European NF brick, 240 × 71 × 115 mm | 10 mm | 49.4 | 4.59 | 20.3 | 18 L per m² |
| Australian brick, 230 × 76 × 110 mm | 10 mm | 48.4 | 4.50 | 20.6 | 17 L per m² |
| US concrete block (CMU), 15 5/8 × 7 5/8 in | 3/8 in | 12.1 | 1.13 | 82.6 | see below |
| Concrete block, 440 × 215 × 100 mm | 10 mm | 9.9 | 0.92 | 101.3 | 7 L per m² |
| AAC block, 600 × 250 × 200 mm | 3 mm thin joint | 6.6 | 0.61 | 152.6 | 3 L per m² of adhesive |
The joint changes the count more than people expect: modular brick with 1/2 in joints drops from 6.86 to 6.44 per ft². German masons often lay NF bricks with a 12 mm bed joint, which gives 48 per m² instead of 49. Choose your unit, then correct the joint if yours differs.
Two-leaf walls, cavities and veneers
- Single leaf: a garden wall, a partition, or the brick veneer on a timber-frame house (one brick thick, about 4 in or 10 cm).
- Two leaves: a solid one-brick wall, or a cavity wall with a brick outer leaf and a block inner leaf. For a cavity wall of brick and block, run the calculator twice, once for each leaf.
- Hollow concrete blocks: mortar usually goes only on the face shells, and some cores are filled with grout and rebar. The joint volume the calculator gives for CMU is an upper bound for the joints alone and does not include core fill.
Ordering
Bricks are sold by the thousand in the US, by the pack or pallet in the UK and Europe. Pack sizes vary (a few hundred bricks), so ask for the exact count and round up to whole packs. Order a single delivery: bricks from different firings can differ in color, and mixing bricks from several packs as you lay them evens out the shade.
Walls that carry a roof or floor, retaining walls and anything higher than a garden wall need a design by an engineer or a builder who knows the local code. For the footing under the wall, use the concrete calculator.
Once zet4u is saved on your phone, the calculator works offline, in the builders’ yard as well.
Frequently asked questions
How many bricks are in a square foot?
6.86 US modular bricks (7 5/8 × 2 1/4 in face) with 3/8 in mortar joints, or about 6.44 with 1/2 in joints. In a square meter: 73.8 modular bricks, 59.3 UK bricks (215 × 65 mm with 10 mm joints, the 60 per m² builders quote), 49 European NF bricks or 48 Australian bricks.
How many bricks for a 10 ft wall?
A wall 10 ft long and 8 ft high is 80 ft², so 549 modular bricks for one leaf, or 576 with 5% extra. A double (two-leaf) wall needs twice as many.
How much mortar do I need per 1,000 bricks?
For US modular bricks with 3/8 in joints the joints themselves hold about 0.23 m³ (8 ft³) per 1,000 bricks; UK bricks with 10 mm joints about 0.30 m³. In practice add a good margin, since mortar is always lost on the board and in the cavity. Mortar bags state how many bricks they lay.
What size is a standard brick?
It depends on the country. US modular: 7 5/8 × 2 1/4 × 3 5/8 in (ASTM C216). UK and Ireland: 215 × 65 × 102.5 mm. Germany's Normalformat (NF): 240 × 71 × 115 mm. Australia: 230 × 76 × 110 mm. Each is sized so that brick plus joint makes a round module.
Sources
- Brick Industry Association, Technical Note 10: Dimensioning and Estimating Brick Masonry
- NIST Special Publication 811: Guide for the Use of the SI, Appendix B (inch, square foot)
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