Brick Calculator

Wall, coverage, waste — in that order

The worked wall: 20 × 8 ft = 160 sq ft − 40 sq ft of openings = 120 sq ft. Modular brick covers 675 units per 100 sq ft (BIA Technical Note 10, Table 4 — a figure that already includes the ⅜ in joint, because a modular brick's nominal 8 × 2⅔ in face is the brick plus its joint), which is 6.75 bricks per square foot, so the net wall needs 810 bricks. BIA's minimum 5% breakage allowance lifts that to 850.5, rounded up to 851 bricks with 0.5 of a brick to spare. Computed at build time by the same engine wired to the form: if the engine changed, this paragraph would change with it, or the build would fail.

Three figures on this page come from outside the arithmetic — the per-size counts in the dropdown, the mortar yield that appears for standard brick, and the waste default. Where each one comes from, what kind of figure it is, and how a test pins it so it cannot drift is the subject of the guide Coverage figures and where they come from, and that material is not repeated here. The rest of this page explains what the brick engine does with those figures — stage by stage, input by input — and how to read what comes back.

The five stages, in order

Every estimator on the site runs the pipeline documented on the methodology page: geometry, coverage, waste, round-up, and a cost only if you price it. For brick the stages look like this, with the veneer wall carried through each one.

1. Geometry. Wall length × wall height, both in feet, is the gross wall area in square feet, and the openings area is subtracted from it to give the net area — the wall that will actually be faced. Metric entries are converted to feet and square feet before this step, so the engine always works in one set of units. The veneer wall: 20 × 8 = 160 sq ft, less 40 = 120 sq ft. The engine refuses a zero or negative dimension, and it refuses an openings figure as large as the wall itself, with a message that says to check both figures.
2. Coverage. The net area is divided by the wall area one brick accounts for, which is 100 sq ft ÷ the BIA count for the chosen size. For modular brick that is 100 ÷ 675 = 0.1481 sq ft per brick, and 120 ÷ 0.1481 = 810 bricks — the same arithmetic as 120 × 6.75 per square foot, which is how the result box prints it. This is the net quantity: what the geometry needs with nothing added and nothing rounded. Because the BIA count already contains the ⅜ in joint, no joint allowance is added here or anywhere else in the chain.
3. Waste. The breakage percentage is applied to the brick quantity as bricks × (1 + waste ÷ 100): 810 × (1 + 5 ÷ 100) = 850.5. It is applied before any rounding so the margin is counted exactly once. The default is BIA's "at least 5 percent" added to net brick quantities — a trade convention with a primary source, and the one waste figure on this site that has one — and the field accepts any value from zero to one hundred.
4. Round-up. The waste-adjusted quantity is rounded up to a whole brick: 850.5 becomes 851, and the 0.5 of a brick you did not need is reported as spare. This is the only rounding on the brick count. Every intermediate value keeps full precision and is rounded for display alone, and a quantity that lands within one part in a billion of a whole number is treated as whole, so a floating-point artifact never buys a phantom brick — one of the worked examples below shows that guard doing its job.
5. User price. If you type a price per brick, the cost is that price times the rounded count — the bricks you buy, not the bricks you lay. Leave the field blank and no cost line appears. The tool holds no price table and suggests no figure; every cost on this site is the number you typed, multiplied.

Mortar runs as a side branch off the second stage, and only when the size is standard. The net laid count is divided by the manufacturer's 37 standard bricks per 80 lb bag and rounded up: the veneer wall in standard brick needs 786 bricks net, and 786 ÷ 37 = 21.243, so 22 bags. It is figured on the net count rather than the waste-adjusted one because a brick that breaks on the pallet is never bedded in mortar. Neither the waste field nor the price field touches the mortar line; only the net wall area and the size do, and for every size other than standard the line is absent rather than guessed.

Why each input matters

Units. Imperial mode takes feet for the two wall dimensions and square feet for the openings. Metric mode takes metres and square metres and converts them with exact factors — 0.3048 m per foot for the lengths and 0.09290304 m² per square foot for the openings, both consequences of the international definition of the foot — before the engine sees them. The arithmetic downstream is identical in both systems; in metric mode the result box reports the net wall area in square metres, and the brick count is the same count the converted feet would give. The BIA figures are never converted, because a brick is the same size whichever way the wall was measured.

Wall length. The run of wall to be faced, in decimal feet. The engine treats whatever it receives as one straight rectangle, so for a wall that turns corners add the runs and enter the total, or run the tool once per wall. A tape reading in feet and inches is converted first — the feet & inches calculator does that arithmetic. The gross area, and with it every line of the result, scales with the length directly.

Wall height. In feet — not inches, and not courses. The engine counts by area rather than by whole courses, so a height that does not land on a course module simply contributes its partial area; whether that partial course is cut or the height adjusted is a layout decision the model does not make. A height typed in inches is the misreading discussed below.

Openings to subtract. The combined area of every door, window, and gap in the wall, in square feet (square metres in metric mode), default zero. It is an area, not a count and not a dimension: a 3 × 7 ft door is 21 sq ft, and several openings go in as one total. Openings come off the area before the coverage stage, so the bricks that would have filled them are never counted — and the cutting around them is left to the waste percentage, which is one reason the default is described as a floor.

Brick size. The dropdown changes one number: the BIA count per 100 sq ft that the net area is multiplied by. Modular at 675 and standard at 655 are the two everyday sizes and lead the list; the other 10 named sizes run down to 300 for utility. The count is the whole difference between sizes — the same wall in utility brick needs fewer units by exactly the ratio of the two counts, and the long wall below shows it. Choosing standard also switches on the mortar line, because that is the one size the manufacturer's bag yield is stated for.

Waste. The default of 5% is BIA's "at least 5 percent" added to net brick quantities — a convention with a primary source, and still a convention, which is why the field is editable. Enter zero to see the pure geometry count plus the round-up; enter more for corners, arches, and soldier courses, as the FAQ says. Each percentage point on the veneer wall is 8.1 bricks. The guide Waste factors, explained covers how to choose a figure for your own layout and crew.

Price per brick. Optional, and supplied only by you. Enter a price and the cost is that price times the rounded brick count; leave it blank and no cost line appears. The multiplication uses the rounded count deliberately — a brick you must buy but will not lay is paid for in the estimate, as it would be at the register. Mortar is counted but never priced.

The figures this page relies on, and their status

• Bricks per 100 sq ft, by size — a published industry table: Brick Industry Association Technical Note 10, Table 4, for a single-wythe wall in running or stack bond with a ⅜ in joint. 12 named sizes, from 300 (utility) to 675 (modular). Not adjustable; choosing a size chooses the figure.
• Wall area per brick — arithmetic: 100 sq ft ÷ the count. 0.1481 sq ft for modular, 0.1527 for standard — the same division the engine runs, at full precision and rounded here only for display. The build checks that the engine's net count for every example on this page is reproduced from this figure, so the prose cannot keep agreeing with itself if the engine's basis changed.
• Mortar, 37 standard bricks per 80 lb bag — a manufacturer figure from the QUIKRETE Mortar Mix No. 1102 product data sheet, stated "up to" and stated for standard brick only. Fixed in this tool, with no field to change it, and applied to no other size.
• Waste default 5% — a trade convention with a primary source (BIA Technical Note 10, "Brick Breakage and Waste": "at least 5 percent"); adjustable.
• Unit factors — 12 in per foot, 0.3048 m per foot, and 0.09290304 m² per square foot — definitions, all exact; the metric ones are used only to convert metric entries into the engine's feet and square feet.

How the site sources, labels, and tests each of these is the guide's subject; this list says only which of them this page depends on and what kind of figure each one is.

Worked examples

Every figure below was produced at build time by the engine that runs the form above. The inputs are chosen to show different behaviours of the pipeline — a change of size, a change of waste, an exact fit, a fractional count with no allowance, a metric entry, and a priced wall. The table summarises them; each wall is then taken through in detail.

The veneer wall in modular and in standard brick

The same 120 sq ft of net wall, two sizes. In modular brick: 810 net, 850.5 with waste, buy 851, no mortar line. In standard brick, at BIA's 655 per 100 sq ft for the 3⅝ × 2¼ × 8 in specified face: 786 net, 825.3 with waste, buy 826 with 0.7 spare — 25 fewer than modular, because the standard count per 100 sq ft is lower. Switching to standard also adds the mortar line: 786 ÷ 37 = 21.243, rounded up to 22 bags. The mortar count carries no waste and rests on an "up to" yield, so read it as a floor rather than a ceiling.

The veneer wall at 0%, 5%, and 10% waste

The same 810 net bricks buy 810 at zero waste (0 spare, because the net count happens to be whole), 851 at the default (0.5 spare), and 891 at 10% (0 spare). The last of those is the exact-fit guard at work: 810 × (1 + 10 ÷ 100) evaluates in binary floating point to 891.0000000000001, a hair above the whole number, and a naive round-up would buy 892. The engine treats a quantity within one part in a billion of a whole as exact, so the count is 891 and nothing is bought for a rounding artifact. On this wall each percentage point of waste is 8.1 bricks.

A garden wall in queen brick: 30 × 4 ft

Nothing to subtract, so the net area is the gross 120 sq ft. Queen brick is listed at 550 per 100 sq ft — BIA's published count for its specified face, not a nominal-face calculation — so 120 × 5.5 = 660 bricks net. The 5% allowance makes that 693, which is itself a whole number, so the purchase is 693 with 0 spare. The allowance and the rounding remainder are two different things: here the allowance is present and the remainder is zero. No mortar line, because queen is not the size the bag yield is stated for.

A small wall at zero waste: 15 × 7 ft

105 sq ft × 6.75 = 708.75 modular bricks — fractional, because the area is not a whole number of nominal faces. With the waste field set to 0 the adjusted quantity is still 708.75, and the round-up buys 709 with 0.25 of a brick spare. Setting waste to zero removes the allowance, not the rounding: a fractional count always rounds up, and the spare figure shows exactly what the rounding bought.

A long wall with openings, in utility and in modular brick: 40 × 10 ft

40 × 10 = 400 sq ft, less 96 sq ft of openings, is 304 sq ft net. In utility brick, at 300 per 100 sq ft: 912 net, 957.6 with waste, buy 958 with 0.4 spare. The same wall in modular brick: 2,052 net, 2,154.6 with waste, buy 2,155. The net counts stand in the ratio of the two BIA figures, 675 ÷ 300 = 2.25, exactly; only the round-up at the end breaks the proportion, and only by a fraction of a brick.

Metric: 6 × 2.4 m with 3.7 m² of openings

In metric mode the form converts before the engine runs: 6 m ÷ 0.3048 = 19.685 ft, 2.4 m ÷ 0.3048 = 7.874 ft, and 3.7 m² ÷ 0.09290304 = 39.8265 sq ft. Gross area 155 sq ft (14.4 m²); net 115.17 sq ft, presented back as 10.7 m². In modular brick: 777.42 net, 816.29 with waste, buy 817 with 0.71 spare. The BIA count was not converted — it is the same 675 per 100 sq ft applied to the converted area — and the unit toggle changed what you typed and what is printed back, never the path through the engine.

A priced wall in engineer modular brick: 24 × 10 ft

240 sq ft less 60 sq ft of openings is 180 sq ft net. Engineer modular is listed at 563 per 100 sq ft, so 180 × 5.63 = 1,013.4 net, 1,064.07 with waste, buy 1,065 with 0.93 spare. Suppose you typed $0.50 into the price field as a stand-in for whatever your own supplier quoted — the site holds no brick price and suggests none. One line is added to the result: 1,065 × $0.50 = $532.50. Nothing else moves. The cost multiplies the rounded count, so the 0.93 of a spare brick is paid for, as it would be at the register.

Reading the output

The first line is the purchase count — bricks after waste and the round-up, the number to give the yard. The second shows the net wall area (square feet, or square metres in metric mode) multiplied by the bricks per square foot for your size to give the net count: that per-square-foot figure is the dropdown's per-100-sq-ft count divided by 100, shown to two decimals, and the engine used the full-precision value. The third line is the waste-adjusted quantity, still fractional, with the percentage that produced it. For standard brick a fourth line gives the mortar bags at the manufacturer's 37 bricks per bag. A cost line appears only when you have entered a price. Read the second line to check your geometry, the third to check your allowance, and the first to place the order; the copy button places the purchase count, the net area, and the mortar bags on the clipboard as one plain-text line.

Common misreadings

Wall dimensions in inches. On the concrete tools the classic slip is a thickness typed in feet; on this page it is the two wall fields typed in inches. Enter the veneer wall as 240 × 96 and the engine sees a 23,040 sq ft wall — 144 times the real area, because 12 × 12 = 144 — and counts 163,013 bricks instead of 851. If the count looks like a warehouse, check the two wall fields first. Both take feet.

Metric figures in the imperial fields. The metric wall above is 6 × 2.4 m with 3.7 m² of openings. Type those same numbers with the toggle still on Imperial and the engine sees a 6 × 2.4 ft wall less 3.7 sq ft: 10.7 sq ft net and 76 bricks, against the correct 817. If the count looks implausibly small for the wall, check the toggle.

Openings entered as a count or a dimension. Typing 2 for two windows subtracts 2 sq ft: the veneer wall then counts 1,120 bricks instead of 851, overbuying by 269. Typing a door's height alone subtracts a strip rather than the door. The field wants width × height, summed over every opening — 3 × 7 = 21 for the door above.

Waste as a fraction. The waste field takes a percentage. The veneer wall at 5% buys 851; typed as 0.05 it is read as 0.05%, the adjusted quantity falls to 810.41, and the purchase drops to 811 — 40 bricks short of the intended allowance, with no warning, because a fraction of a percent is a valid entry.

Per square foot and per hundred. The dropdown shows each size's count per 100 sq ft; the result box shows the same figure per square foot. They are one number: 675 per 100 sq ft is 6.75 per square foot. Multiplying the net area by the per-100 figure without dividing by 100 produces a count a hundred times too large.

Adding a joint allowance. The BIA counts already include the ⅜ in joint. Counting from the specified brick face, or adding a joint allowance on top of the nominal count, counts the joint twice and overbuys. A different joint size is a different count — BIA's note covers that correction — not an addition to this one.

Reading the net count as the purchase count. 810 is what the geometry needs; 851 is what to buy. The allowance and the round-up sit between the two lines on purpose, and a count rounded down would leave the wall a brick short.

Reading the mortar bags as waste-inclusive. They are not. The 22 bags on the standard-brick veneer wall carry no waste allowance and rest on a yield the manufacturer states as "up to". BIA's note suggests adding a further allowance to net mortar quantities for waste, and this tool does not apply one.

Where the model stops

This is a purchasing count, and the site estimates material quantities only. It does not determine whether a brick wall is adequate for any purpose, whether it complies with a building code, what footing, reinforcement, lintels, or ties a wall needs, how many wythes it should have, or whether a permit applies — those questions belong to a licensed engineer or your building department, exactly as the note under the form says.

Within its own job, the model simplifies. It counts one wythe of stretcher-equivalent area in running or stack bond with a ⅜ in joint, which is what the BIA table assumes; a thicker joint, a header-course bond, or a second wythe changes the count, and the correction factors for those cases are in BIA's note rather than in this tool. The wall is one straight rectangle: corners, piers, returns, arches, and soldier courses are left to your layout and to the waste percentage, which is a single flat figure on the brick quantity. The mortar yield is applied to standard brick alone, carries no waste, and is an "up to" figure the tool treats as exact. Pallet and cube quantities, delivery minimums, regional product variation, and anything that is not a brick are outside the model, and so is any price it did not receive from you. The methodology page lists the simplifications every estimator shares.

Masonry neighbors

Building with 8 × 16 block instead? The concrete block calculator runs the same wall-area method on the nominal CMU face. Paving rather than stacking — a patio or path — is the paver calculator's job, and if the project includes setting posts or a footing, size the pour with the concrete bag calculator. The square footage calculator settles the area of a wall that is not one rectangle, and the feet & inches calculator turns tape readings into decimal feet.

The concept pages behind this tool are Coverage figures and where they come from and Waste factors, explained; the full list is on the guides index, and the shared pipeline is on the methodology page.

Frequently asked questions

Wall dimensions never leave your browser. Coverage sources and the estimating pipeline are documented on the methodology page.