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Brick Calculator
Enter the wall, the brick and the joint. Openings come off the area, and the order is shown apart from the net count.
The formula
Worked example
A 20 ft × 8 ft wall in modular brick, ⅜ in joints, no openings
- (7.625 + 0.375) × (2.25 + 0.375) = 21 in² per brick face plus its joints
- 144 ÷ 21 = 6.86 bricks per ft²
- 20 × 8 = 160 ft² → 160 × 6.857 = 1,098 bricks in the wall
- + 5% for breakage = 1,152 to order
Where this goes wrong
Modular brick does not lay 6.86 to the square foot
Run the formula on a modular brick — 7⅝ long, 2¼ high, ⅜ joints — and you get 6.86 per square foot. The Brick Industry Association publishes 675 per 100 square feet, which is 6.75. Neither is a mistake. Modular brick is sized so that three courses come to exactly 8 inches, which forces a bed joint of about 7⁄16 in rather than ⅜, and that extra sixteenth of an inch removes eleven bricks from every hundred square feet. Order to 6.86 and you are 1.6% over; on a 1,000 brick job that is sixteen bricks, which is cheap. Design a 32 in opening to 6.86 and the coursing will not land.
Questions
- How many bricks are in a square foot?
- It depends entirely on the brick, which is why this page asks rather than assumes. With ⅜ in joints the Brick Industry Association publishes 675 per 100 square feet for modular brick, 655 for standard, 550 for queen and 300 for utility — a spread of more than two to one. Any calculator that answers "about seven" without asking which brick you have is guessing on your behalf.
- Why does this page not estimate the mortar?
- Because we could not reproduce the published figures reliably. Deriving mortar volume geometrically — wall volume minus brick volume — matches the BIA table for modular brick to within half a percent, but is far off for several non-modular sizes, and we could not establish why. Rather than publish a number that is right for one brick and wrong for another, this page leaves it out and points you at BIA Technical Notes 10, Table 4, which lists it per brick size.
- Should I subtract the windows and doors?
- For ordering, yes — that brickwork does not exist, and on a wall with a patio door and two windows the openings can be a fifth of the face. Enter their total area and the count comes down accordingly. Keep the waste allowance, though: cutting brick around an opening produces more breakage, not less.
- How much waste should I allow?
- BIA Technical Notes 10 says at least 5% is added to net quantities as a general rule, and that particular job conditions or experience may warrant more. That is the default here. Patterned bonds with headers need more brick again — the same document tabulates the correction factor for each bond.