Brick Calculator

How the brick count is worked out

Brick counting comes down to one idea: each brick takes up its face size plus one mortar joint in each direction. A modular brick is 7-5/8 inches long and 2-1/4 inches high. With a 3/8 inch joint it occupies a patch of wall 8 inches long and 2-5/8 inches high, or 21 square inches. One square foot is 144 square inches, so 144 divided by 21 gives 6.86 bricks per square foot.

The full recipe has three steps. First, find the net wall area: length times height, minus the area of doors and windows. Second, divide that area by the face area of one brick plus its joints. Third, round up to a whole brick and add a waste allowance.

Nominal sizes and the joint convention come from the Brick Industry Association's Technical Note 10, which lists specified and nominal dimensions for clay brick. ASTM C216 is the standard specification for facing brick that sets the tolerances behind those numbers. The calculator on this page uses the same face-plus-joint method, so you can change brick type, joint width and waste without redoing the arithmetic by hand.

Bricks per square foot for the common brick sizes

Brick size is the biggest lever on the count. A king-size brick covers almost twice the wall of a modular brick, so the same wall needs far fewer of them. The table below uses a 3/8 inch joint, the width most residential work is laid to, and a single wythe wall, which is one brick thick.

One caution on the numbers. The Brick Industry Association's own quantity table lists 675 modular bricks per 100 square feet, which is 6.75 per square foot, while the strict 3/8 inch joint math here gives 6.86. The gap comes from coursing: the industry table uses the nominal 2-2/3 inch height, where three courses add up to exactly 8 inches, and a true 3/8 inch joint makes a slightly shorter course. Both figures order the same pallets, and the difference is under 2 percent.

A 120 square foot wall takes 823 modular bricks but only 576 king bricks. The difference is 247 bricks, which is real money once you add delivery and the labor to lay them. Buy the size that matches the wall you are copying. Mixing sizes in one wall means cutting brick at every transition, and cuts cost more time than the brick saves.

Two other sizes show up in older US housing. Engineer modular is 7-5/8 by 2-3/4 inches and counts like a queen brick. Roman brick is long and low at 11-5/8 by 1-5/8 inches, which lands near 6.0 bricks per square foot with a 3/8 inch joint. If your house was built before 1950, measure a loose brick or the exposed face of one in a corner before you order.

What a wider mortar joint does to the count

The joint counts as brick, so a fatter joint means fewer bricks and a wider wall. Going from a 3/8 inch joint to 1/2 inch cuts the count by about 6 percent on the same wall. Going the other way to 1/4 inch adds about 7 percent. That is enough to change how many pallets you buy.

Joint width is not a free choice. It sets the coursing height, and coursing has to line up with window sills, lintels and the top of the wall. A 3/8 inch joint is standard for a reason: three courses of modular brick plus joints come to 8 inches, which matches the 8 inch module used by most other building products. A 1/2 inch joint breaks that alignment and shows up as a thicker, softer looking wall.

Cold weather pushes masons toward the wider end of the range, because mortar that is stiff from the cold is harder to strike to a tight joint. In that case order to the joint you will lay, not to the drawing. If the mason says the joint will run 1/2 inch, use 1/2 inch in the calculator.

Why you add 10 percent, and when 5 percent is enough

No wall uses exactly the number of bricks the area math gives you. Corners need half bricks or cut bricks. Openings need cuts on both sides. A pallet arrives with a few chipped units. Someone drops a stack. Ten percent covers all of that on a normal rectangular wall, which is why it is the default here.

Five percent is enough when the wall is long, straight, has no openings and uses a running bond with no special corners. Fifteen percent is closer to right when the wall has several openings, a curved section, a soldier course, or a herringbone pattern. Herringbone is the hungry one: the pattern cuts a large share of every brick, so the waste can reach 20 percent on a small panel.

Keep the extra bricks. Matching a dye lot two years later is hard, and a box of spares in the garage is cheaper than a special order for 20 bricks. Store them off the ground and out of the rain so they do not spall in freezing weather.

Worked example: a 20 by 8 foot wall with a garage opening

Take a 20 foot long wall that is 8 feet high, with a 40 square foot opening for a garage window and a vent. The wall area is 20 times 8, or 160 square feet. Subtract the 40 square feet of openings and 120 square feet of brick remain.

With modular brick and a 3/8 inch joint, one brick covers 21 square inches, so 144 divided by 21 is 6.86 bricks per square foot. Multiply 120 by 6.86 and you get 822.86, which rounds up to 823 bricks. Add 10 percent and the order becomes 906 bricks. At $0.65 a brick that is $588.90, before mortar, ties and delivery.

The same wall in standard brick needs 787 bricks, or 866 with waste. In queen brick it needs 692, or 762 with waste. In king brick it drops to 576, or 634 with waste. Those are the four options in the calculator, and switching between them is the fastest way to see what a size change costs.

Courses, corners and bond pattern

A course is one row of brick. The number of courses is the wall height in inches divided by the height of one brick plus one joint. An 8 foot wall is 96 inches, and 96 divided by 2.625 is 36.57, so the wall runs 37 courses. That last course gets cut, which is normal and is why the wall is usually detailed to end on a whole course.

Bricks per course is the wall length in inches divided by the length of one brick plus one joint. At 20 feet, or 240 inches, that is 240 divided by 8, or 30 bricks per course. Multiply 30 by 37 and you get 1,110, which is more than 823. The gap is the opening: the courses that cross the window are short, and the calculator takes that out through the area subtraction instead of counting brick by brick.

Bond pattern changes the cut count, not the coverage. Running bond offsets each course by half a brick and needs a half brick at every other end. Stack bond lines the joints up and needs fewer cuts but more reinforcement. English and Flemish bond mix headers and stretchers, which changes the look and adds handling time. None of them change bricks per square foot much, but all of them change how many bricks break on site.

Wall sizes at a glance

The table below uses modular brick, a 3/8 inch joint and 10 percent waste, and already subtracts the openings shown. Use it to sanity check the calculator before you order.

A double wythe wall, which is two bricks thick with a cavity between, doubles the count. A brick veneer over wood framing is a single wythe and counts like the table. Garden walls often sit on both sides of a pier, so measure each face separately and add them.

Cost, delivery and where the estimate stops being exact

The cost line multiplies bricks by the price you pay per brick. That price is usually quoted per thousand on a pallet, so divide by 1,000 before you type it in. A cube of brick is 500 bricks and a pallet is often 500 to 600, so ordering in round pallets can beat ordering the exact count plus a few.

Three things are not in the number. Mortar is sold separately, usually as bags of preblended mix or as sand and cement. Wall ties, flashing and weep holes are separate line items. Labor is the largest cost on most walls and depends on the bond, the height and how much cutting the openings need. Ask for a quote that lists brick, mortar and labor apart so you can see which one moved.

The estimate is geometric, not structural. It does not check whether the wall needs reinforcement, a lintel over an opening, or a footing sized for the soil. Those are engineering questions. For a low garden wall the arithmetic is enough; for anything carrying a roof or holding back soil, have the details checked before you buy material.