Calculation method
Subtract major openings from wall area. Divide the net area by (actual brick face length + joint) × (actual brick face height + joint), converted from square inches to square feet. Add the chosen brick allowance and round up. Divide the whole-brick count by the editable mortar-bag yield and round up again.
Worked example: input to purchase quantity
A 20 ft × 8 ft wall less 16 ft² of openings has 144 ft² of brick face. A 7⅝ × 2¼ in modular brick with ⅜ in joints occupies an 8 × 2⅝ in module, or 0.145833 ft². The area estimate is 987.43 bricks; with 10% extra, buy 1,087 bricks. At an illustrative 37 bricks per mortar bag, plan 30 bags.
Measure the brick face that will be built
This worksheet estimates a simple, single-wythe brick face. Measure wall length and height, then separately measure the combined area of large doors and windows that will not receive brick. The net area is gross rectangular wall area minus those openings. For several distinct walls, estimate each section separately when heights, brick choices, joint widths or openings differ. Do not treat the face-area result as a count for a thicker wall, columns, a fireplace, steps, returns or a special bond pattern.
Enter actual brick face dimensions, not a nominal product name. The modular starting choice uses a 7⅝ in face length and 2¼ in face height. Adding a ⅜ in head joint gives an 8 in horizontal module; adding the bed joint gives a 2⅝ in vertical module. The selector also offers a standard face and an engineer modular example. Those are planning choices from a manufacturer catalog, not a promise that every brick sold under a similar name has identical dimensions. Check the specific product data, orientation and intended bond before buying.
Follow the arithmetic
For a running-bond area estimate, one brick and its share of surrounding joint occupy a rectangular module: (actual face length + head joint) × (actual face height + bed joint). Because both dimensions are entered in inches, divide the square-inch product by 144 to get square feet. Divide net wall area by that module area for a decimal brick count. Apply the editable extra percentage for cuts and breakage, then round upward to whole bricks. The tool uses one joint-width input for both directions; if the specified head and bed joints differ, prepare a more detailed takeoff.
The default 20 by 8 ft wall contains 160 ft² before openings. Subtracting 16 ft² leaves 144 ft². The 8 by 2⅝ in module has 21 square inches, so 144 ÷ (21 ÷ 144) = 987.43 bricks. Ten percent extra gives 1,086.17 and rounds to 1,087 bricks. This is a purchase allowance on the estimated brick count; it does not add another layer of brick to the wall or replace the layout of corners, jambs and soldier courses.
Plan mortar as a separately checked allowance
The mortar-bag output divides the rounded brick order by the entered number of bricks laid per bag. Its starting value of 37 comes from one 80 lb mortar mix reference that says up to 37 standard bricks. Actual consumption changes with brick size, joint width, brick absorption, waste and workmanship. The 37-brick figure is a rough product reference even when the modular preset is selected. Replace it with the yield for the exact mortar and unit you intend to buy. The tool does not compute mortar volume from joint geometry, and its bag output should not be used as a specification.
Check whether the quote is for the same bag weight and mortar type. Compare the manufacturer instructions with the masonry specification. If the label gives a different coverage basis, do not silently enter 37. Record the source of the yield next to the estimate. For the default example, 1,087 ÷ 37 = 29.38, which rounds upward to 30 bags. If a supplier confirms only 30 bricks per bag for the project, the same brick order becomes 37 bags. The sensitivity shows why the editable yield matters.
Use a sketch before ordering
Mark wall ends, corners, movement joints, lintels, openings, bond changes and any decorative courses on an elevation drawing. Subtract only the openings you truly omit; a narrow opening can still create many cuts and little reusable material. Check whether brick is sold by the piece, cube or pallet, and convert the whole-brick result to the supplier's purchasable unit separately. Keep spare bricks for later repairs only if their color and lot match your plans.
This calculator does not assess structural capacity, supports, flashing, moisture management, anchors, fire requirements or code compliance. It counts an idealized exposed face using an area module. Site conditions and the masonry design govern the construction method. Recheck measurements, actual face size, mortar joint, opening deduction and product yield before placing an order.
Product and method reference
Reference limits and default yields are identified separately from user-entered values; verify the adopted local code and current product label. Brick Industry Association Technical Note 10.
Calculation and editorial review: November 3, 2026. Arithmetic runs in your browser; project inputs are not submitted to TwoCut.