A wall of modular brick with 3/8 in mortar joints takes 6.75 bricks per square foot, or 675 per 100 sq ft, according to the Brick Industry Association (BIA). A 20 ft wall 4 ft high is 80 sq ft, so it needs 540 bricks, 567 with 5% for breakage, and about 17 bags of 80 lb mortar. Queen, king and utility brick are larger, so they take fewer bricks per square foot; the table below has each size.
How the brick count is calculated
For a wall the calculator uses BIA Technical Note 10, Table 4, which lists the number of bricks per 100 sq ft of wall and the mortar it takes for every common size and for 3/8 and 1/2 in joints:
bricks = (length × height − openings) × bricks per sq ft × wythes × (1 + waste)
Laid flat, one brick covers (length + joint) × (width + joint). Around a circle, each course takes the centerline circumference ÷ (brick length + joint), rounded up.
Worked example: a 20 ft garden wall
The calculator opens on one wall, 20 ft long and 4 ft high, in modular brick with 3/8 in joints, single wythe:
- 20 ft × 4 ft = 80 sq ft.
- 80 sq ft × 6.75 = 540 bricks laid.
- 540 × 1.05 = 567, so buy 567 bricks.
- Mortar: 540 × 1.15 ÷ 37 bricks per bag = 17 bags of 80 lb Quikrete Mason Mix. BIA puts the mortar in the wall itself at 4.4 cu ft; bags follow what one bag lays in practice.
Bricks per square foot by size
From BIA Technical Note 10, Tables 1, 2 and 4, for a 3/8 in joint (no waste):
| Brick | Size (W × H × L) | Bricks per sq ft | Mortar per 100 sq ft |
|---|---|---|---|
| Modular | 3⅝ × 2¼ × 7⅝ in | 6.75 | 5.5 cu ft |
| Engineer modular | 3⅝ × 2¹³⁄₁₆ × 7⅝ in | 5.63 | 4.8 cu ft |
| Norman | 3⅝ × 2¼ × 11⅝ in | 4.50 | 5.1 cu ft |
| Utility | 3⅝ × 3⅝ × 11⅝ in | 3.00 | 3.7 cu ft |
| Queen | 2¾ × 2¾ × 7⅝ in | 5.50 | 6.7 cu ft |
| King | 2¾ × 2⅝ × 9⅝ in | 4.55 | 6.5 cu ft |
| Standard | 3⅝ × 2¼ × 8 in | 6.55 | 9.5 cu ft |
Brick names vary between plants, so match the actual dimensions; the calculator holds all twelve BIA sizes.
Bricks for a house
Pick Wall, then House, four walls, and enter the outside length, width and wall height. A 40 × 30 ft house with 9 ft walls has 1,260 sq ft of wall; take off 12 windows of 3 × 4 ft and 1,116 sq ft is left. That is 7,533 bricks laid, 7,910 to buy, and 235 bags of mortar. Add gable ends as a separate wall of half their width times their height.
Single or double wythe
A wythe is one brick thick. House veneer is a single wythe; a freestanding wall is often two, which doubles the brick and adds the collar joint: 3.13 cu ft of mortar per 100 sq ft at 3/8 in (BIA Table 5).
Brick patio and walkway
For a patio or walkway the bricks lie flat. Sand-set brick is laid hand-tight on a compacted base, which takes 5.21 modular bricks per sq ft; a 12 × 10 ft patio needs 625, 657 with waste. With 3/8 in mortar joints each brick covers 8 × 4 in and the count drops to 4.5 per sq ft, 567 for the same patio, plus about 3.1 cu ft of mortar in the joints (5 bags). The mortar joints need a concrete slab under them; work that out with the concrete slab calculator.
Bricks for steps
Three steps 4 ft wide with 7 in risers and 12 in treads have 7 sq ft of riser face (47 bricks) and 12 sq ft of tread laid flat (54 bricks): 107 bricks with waste and 4 bags of mortar. Brick steps are usually a veneer over a concrete core; the concrete steps calculator gives the concrete for it.
Fire pit and round column
In Fire pit mode, a ring 48 in across the outside, in modular brick laid as stretchers around the ring, has a centerline of 44⅜ in. π × 44⅜ in ÷ 8 in = 17.4, so 18 bricks per course; six courses make a 16 in high pit: 108 bricks, 114 with waste, and a 40¾ in fire bowl inside. A second ring adds a liner course inside the first.
A round column is built the same way as a shell with a concrete core. A 24 in column, 48 in high, takes 9 bricks per course over 18 courses, 171 bricks with waste, 6 bags of mortar, and 6.12 cu ft of concrete to fill the 16¾ in core. The concrete bag calculator turns that volume into bags.
Which mortar for brick
BIA Technical Note 8B recommends Type N for most above-grade brickwork and veneer, Type S for loadbearing and reinforced walls, and Type M (or S) at or below grade. Quikrete rates an 80 lb bag of Mason Mix or Mortar Mix at up to 37 standard bricks, Sakrete Type S at 35. For bricks larger than modular, the calculator scales the bag count by the BIA mortar per 1000 bricks: a king brick takes 14.2 cu ft per 1000 against 8.1 for modular. The mortar calculator also works out cement, lime and sand if you mix your own.
What to work out next
- A block backup wall or foundation under the brick: the cinder block calculator.
- The footing the wall stands on: the concrete footing calculator.
- Every block, brick and concrete tool: concrete and masonry calculators.