Brick Calculator
Work out how many bricks a wall needs from its area, the brick size and the mortar joint, with mortar volume and cost.
How to use this calculator
- 1Enter the wall length and height, and the total area of any doors and windows.
- 2Pick the brick size. Modular is the common US face brick; choose Custom to enter measured dimensions.
- 3Set the mortar joint — 3/8 in is standard — then read the brick count, mortar volume and cost.
How the calculation works
bricks per ft² = 144 ÷ ((L + jh) × (H + jb)) bricks = bricks per ft² × A × w × (1 + waste)- L
- Specified face length of the brick, in inches — 7.625 for modular, not the nominal 8
- H
- Specified face height of the brick, in inches
- jh
- Head joint — the vertical mortar joint between brick ends, in inches
- jb
- Bed joint — the horizontal mortar joint between courses, in inches
- A
- Net wall area in ft², after subtracting doors and windows
- w
- Wythes — how many brick layers thick the wall is
Face dimensions are the *specified* size — the brick as manufactured — not the nominal size. A modular brick is specified at 7 5/8 × 2 1/4 in and nominal at 8 × 2 2/3 in; the nominal figure already contains the joint, so adding a joint to it counts the mortar twice.
The joint is added once per dimension, not twice. Each brick owns the joint on one long side and one end; its neighbour owns the other two. This is the same off-by-one that catches people counting fence pickets.
Mortar volume is the wall face area the bricks do not cover, taken through the full depth of the wythe. For modular brick at a 3/8 in joint that lands near 8 ft³ per 1,000 bricks, matching the 7–9 ft³ figure quoted in the trade.
Worked example
A 20 × 8 ft veneer wall in modular brick
- 1.Wall area: 20 × 8 = 160 ft², with no openings to subtract.
- 2.Modular brick is specified at 7.625 × 2.25 in, so with a 0.375 in joint it repeats every 8 × 2.625 in = 21 in².
- 3.Bricks per ft²: 144 ÷ 21 = 6.86.
- 4.Exact count: 160 × 6.857 × 1 wythe = 1,097.1, or 1,098 whole bricks.
- 5.Add 10% waste to the exact figure: 1,097.1 × 1.10 = 1,206.9, rounded up to 1,207 bricks.
- 6.At $0.75 each that is about $905 in brick.
Result: 1,207 bricks, about $905
The same wall with a door and two windows
- 1.Gross area is still 160 ft², but 45 ft² of openings leaves 115 ft² of brickwork.
- 2.Exact count: 115 × 6.86 = 789 bricks.
- 3.Openings mean far more cutting, so the waste allowance rises to 15%: 789 × 1.15 = 907 bricks.
- 4.Subtracting the openings saved about 300 bricks even after the higher waste allowance.
Result: 907 bricks
Matching a published coursing table exactly
- 1.Modular coursing puts three courses in exactly 8 in, so each course is 8 ÷ 3 = 2.6667 in.
- 2.The brick is 2.25 in tall, so the bed joint is 2.6667 − 2.25 = 0.4167 in, or 5/12.
- 3.Head joints stay at 3/8 in, because 7.625 + 0.375 already gives exactly 8 in.
- 4.Bricks per ft²: 144 ÷ (8 × 2.6667) = 6.75 — the Technical Note 10 figure exactly.
- 5.Over 100 ft² that is 675 bricks, against 686 using a uniform 3/8 in joint.
Result: 6.75 bricks per ft², 675 bricks
Specified, nominal and the joint you must not count twice
Every US brick has two sets of dimensions and confusing them is the single most common estimating error. The *specified* size is the brick as it leaves the kiln — a modular brick is 3 5/8 × 2 1/4 × 7 5/8 in. The *nominal* size is the specified size plus one mortar joint, which for modular brick gives the tidy 4 × 2 2/3 × 8 in that lets masonry lay out on a 4 in grid.
This calculator takes specified dimensions and adds the joint itself. If you enter nominal dimensions instead you will be adding a joint that is already there, undercounting the wall by roughly 10%. When in doubt, measure a brick.
Why published tables say 6.75 and the arithmetic says 6.86
Look up modular brick in Brick Industry Association Technical Note 10 and you get 6.75 bricks per square foot. Work it out from 7 5/8 in plus a uniform 3/8 in joint and you get 6.86. The gap is about 1.5%, which on a large job is a pallet.
Both figures are correct, because they answer slightly different questions. Modular coursing is defined so that three courses rise exactly 8 in — that is what makes brick coordinate with block and with window openings. Three 2 1/4 in bricks are 6 3/4 in, so the three bed joints must share the remaining 1 1/4 in, which is 5/12 in each rather than 3/8 in. Head joints stay at 3/8 in, because 7 5/8 plus 3/8 already gives the tidy 8 in length.
That is why this calculator lets the bed joint differ from the head joint. Switch that option on and the default 5/12 in bed joint returns 6.75 exactly, matching the table. Note that simply setting *both* joints to 5/12 in does not work — it gives 6.72, because it widens the head joint that was already correct.
How much mortar, and why the bags run out first
Mortar is whatever the brick faces do not cover, taken through the depth of the wythe. For modular brick at a 3/8 in joint that is about 8 cubic feet per thousand bricks, consistent with the 7–9 ft³ figure used in the trade. Half-inch joints push it past 10.
Mortar waste runs higher than brick waste, so this calculator never applies less than a 10% allowance to it. Mortar left on the board stiffens and must be discarded, batches are mixed in whole bags, and pointing consumes more than the joint geometry suggests. An 80 lb bag of mortar mix yields roughly two-thirds of a cubic foot.
What this does not cover
Brick veneer is a rain screen, not a waterproof layer, and the parts that keep water out are not in this take-off: wall ties at roughly one per 2.67 ft² of wall, flashing at every horizontal interruption, weep holes at 24–33 in centres in the course above the flashing, and a clear cavity behind the brick.
Nor does it cover lintels over openings, control joints, reinforcement, or the foundation the brick bears on. Structural masonry in particular is an engineered assembly — this page sizes the order, not the wall.
What this assumes, and where it stops
Assumptions
- Dimensions entered for the brick are specified (actual) sizes, and the mortar joint is added to them by the calculator.
- Bed and head joints are the same thickness unless you say otherwise, which matches ordinary practice outside modular coursing.
- Mortar volume assumes joints are filled solid through the full depth of the wythe, as required for structural masonry and normal for veneer.
- A mortar bag yield of 0.66 ft³ per 80 lb bag, which is typical for pre-blended Type N and Type S mixes.
Limitations
- Openings are entered as a single total area, so the calculator cannot allow for the extra cutting a large number of small openings causes. Raise the waste allowance instead.
- Bond pattern is assumed to be running bond. Header courses in a Flemish or English bond change the count, because headers present their end rather than their face to the wall.
- Ties, flashing, weep holes, lintels, control joints, reinforcement and the foundation are not included.
- Table figures published by manufacturers use coursing dimensions, which can differ from the geometric result by 1–2%. Neither is wrong; see the article.
Common questions
How many bricks are in a square foot?
For modular brick — the common US face brick — with a 3/8 inch mortar joint it is 6.86 per square foot geometrically, or 6.75 by published coursing tables. Rounding to 7 per square foot is a reasonable field estimate. Queen size runs about 5.8, and larger utility brick about 3.
Should I subtract windows and doors?
Yes, once the openings are large. Leaving them in is a safety margin on a wall with one small window, but a wall that is a third glazing would be overestimated by hundreds of bricks. Subtract the openings and raise the waste allowance to 15% instead, because every opening edge means cut brick.
How much mortar do I need per 1,000 bricks?
Roughly 7 to 9 cubic feet for modular brick with a 3/8 inch joint, and more for wider joints or larger units. That is about 12 to 14 bags of 80 lb pre-blended mix. Buy on the high side: mortar that stiffens on the board cannot be retempered indefinitely and gets thrown away.
What is a wythe?
One continuous vertical layer of brick, one unit thick. Modern brick veneer over a framed or block wall is a single wythe. Older solid masonry walls are two or more wythes bonded together, which multiplies both the brick count and the wall thickness.
Sources
Formula and content last reviewed on .
Results are estimates for information only, not professional advice.
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