Brick Calculator
About Brick Calculation
The Brick Calculator estimates the number of bricks required for a single wall or the walls of a house, accounting for their dimensions, thickness, internal partitions, windows and doors. It also calculates masonry volume, mortar consumption, cement, sand and the length of masonry reinforcement mesh.
The calculation uses wall geometry and brick dimensions, including mortar joints. It is useful for preliminary material estimates, purchasing plans and comparing brickwork options.
Guidelines and recommendations
Calculating wall and partition areas
Masonry geometry. For a rectangular building, the exterior wall perimeter is first determined from the building length and width. Wall thickness is then taken into account to prevent double-counting bricks at corners. Internal walls and partitions are measured according to the selected floor plan, including their connections and intersections.
For a rectangular building, the calculated total length of exterior walls is:
Lwalls = 2 × (A + B) - 4 × t
Here, A and B are the exterior building dimensions in mm and t is the exterior wall thickness in mm. The resulting length is multiplied by the masonry height. For a single wall, the area is calculated directly from its length and height.
Opening area. The area of each window or door type equals its width times height times quantity. Exterior openings are subtracted from exterior wall area, while partition doors are subtracted from partition area. If the total opening area exceeds the corresponding wall area, the calculation is blocked until the dimensions are corrected.
Smasonry = Swalls - Sopenings
All dimensions are converted from mm to m, and areas to m2. Where partitions have a different height, their area is calculated separately.
Gable walls. Each gable is treated as a triangle. Its area is calculated from the base width, height and number of identical gables:
Sgables = (B × H × n) / 2
Here, B is the base width in m, H is the triangle height in m and n is the number of gables. This area contributes to the brick and mortar calculation using the specified gable thickness.
Brick dimensions and masonry thickness
Brickwork module. Brick counts account for the brick dimensions and the mortar joint thickness. A joint thickness of approximately 10 mm is common in ordinary brickwork. The actual value depends on the brick, mortar and construction method.
Wall thickness is calculated from the brick dimensions and the number of bricks across the wall section:
- 0.5 brick:
t = W - 1 brick:
t = L - 1.5 bricks:
t = L + W + j - 2 bricks:
t = 2 × L + j - 2.5 bricks:
t = 2 × L + W + 2 × j
Here, L is brick length, W is brick width and j is the mortar joint thickness. All values are in mm.
For example, with a 250 × 120 × 65 mm brick and 10 mm joints, the calculated wall thicknesses are 120, 250, 380, 510 and 640 mm, respectively.
Dimensional compatibility. The thickness-based brick count follows a common bonding arrangement in which the brick length is approximately twice its width plus a joint. For example, 250 = 120 × 2 + 10 mm. With bricks of substantially different proportions, actual consumption depends on the selected bond pattern.
If exterior walls and partitions use different brick sizes, their quantities are calculated separately. Partitions may also have a separate joint thickness.
Determining the number of bricks
Bricks per masonry area. The count is based on wall area, brick dimensions and joint thickness. For walls thicker than half a brick, a factor reflects the number of half-brick layers across the wall.
N = S × 106 × k / ((L + j) × (h + j))
N is the calculated brick count, S is masonry area in m2, L and h are brick length and height in mm, j is joint thickness in mm, and k is the thickness factor. The multiplier 106 converts m2 into mm2.
The factor k equals 1 for a half-brick wall, 2 for a one-brick wall, 3 for 1.5 bricks, 4 for 2 bricks and 5 for 2.5 bricks.
Rounding the count. Brick quantities for walls, partitions and gables are each rounded up separately to whole bricks. This avoids fractional units. No additional allowance for breakage or cutting is added.
If all masonry sections use the same brick size, their brick counts can be added. If sizes differ, the respective quantities are kept separate.
Masonry volume and mortar consumption
Masonry volume. The area of each wall group is multiplied by its thickness in metres. The volumes of exterior walls, partitions and gables are added, allowing for differing thicknesses.
Vmasonry = S1 × t1 + S2 × t2 + ...
S is the area of the relevant masonry group in m2 and t is its thickness in m. The result is in m3 and includes both bricks and mortar joints.
Mortar volume. This is the difference between the geometric volume of finished masonry and the total volume of bricks without joints.
Vmortar = Vmasonry - Vbricks
The volume of one brick is its length multiplied by width and height. The total brick volume uses the unrounded calculated brick count, avoiding additional rounding errors in the mortar estimate.
Mortar consumption depends on joint thickness and brick dimensions. A larger proportion of joints generally increases mortar volume, other conditions being equal.
Calculating cement and sand
Mix proportions. The preliminary estimate of cement-sand mortar uses the specified ratio of cement to sand by volume. A common example is 1:3: one part cement to three parts sand. The actual mix is selected according to mortar requirements and materials.
Dry-material factor. The loose dry ingredients occupy a different volume from the finished mortar. A factor of 1.3 is used for this estimate: 1 m3 of finished mortar is assumed to require 1.3 m3 of dry ingredients.
The following assumed bulk densities convert ingredient volume to mass:
- Cement: 1400 kg/m3.
- Dry sand: 1600 kg/m3.
Each ingredient mass is determined from its share of the mix. For example, with a cement-to-sand ratio of 1:3:
Mcement = Vmortar × 1.3 × (1 / 4) × 1400
Msand = Vmortar × 1.3 × (3 / 4) × 1600
The results are in kg. Different proportions automatically change the corresponding shares. The 1.3 factor and assumed densities are estimates; actual consumption depends on material properties and the yield of the prepared mix.
Calculating masonry reinforcement mesh
Number of brick courses. Wall height is divided by brick height plus horizontal joint thickness, and the result is rounded up to a whole course.
ncourses = ceil(H / (h + j))
H is wall height, h is brick height and j is joint thickness, all in mm.
Number of reinforcement levels. Mesh is counted from the first course and then at the specified course interval. For example, a wall height of 2700 mm, brick height of 65 mm and a 10 mm joint gives 36 courses. Reinforcing every 5th course results in 8 mesh levels.
Total mesh length is the calculated wall length multiplied by the number of reinforcement levels. Exterior walls and partitions are calculated separately because they can differ in brick size, height and reinforcement spacing.
Additional reinforcement below windows. For each included window, the window width plus 1000 mm is added to the mesh length. This represents a nominal 500 mm extension on each side. The additional lengths are summed across all windows.
For example, four windows each 1200 mm wide add 4 × (1.2 + 1.0) = 8.8 m of mesh. Final mesh length is displayed to 0.1 m.
European standards as reference
Relevant European standards for selecting bricks, mortar and masonry details include:
- EN 1996-1-1: Eurocode 6. Design of masonry structures. Part 1-1: General rules for reinforced and unreinforced masonry structures.
- EN 1996-2: Eurocode 6. Design of masonry structures. Part 2: Design considerations, selection of materials and execution of masonry.
- EN 771-1: Specification for masonry units. Part 1: Clay masonry units.
- EN 998-2: Specification for mortar for masonry. Part 2: Masonry mortar.
- EN 845-3: Specification for ancillary components for masonry. Part 3: Steel meshwork for bed joint reinforcement.
These standards set out requirements for masonry design, materials and workmanship. The geometric formulas and estimating factors above are used to quantify materials; they are not standardised material-consumption rates. Structural details should follow the applicable national annexes to Eurocode 6.
FAQs
Why does the brick count change when the mortar joint gets thicker?
Because bricks take up space together with the mortar between them. A thicker joint increases the module occupied by each brick, so fewer bricks are generally needed for the same area. At the same time, mortar consumption may increase.
Why is a combined brick count not always shown?
If exterior walls and partitions use different brick sizes, the quantities are calculated separately. Adding them into one purchase quantity would mix different products. When all bricks are the same size, their counts are added.
Why is masonry volume much greater than mortar volume?
Masonry volume includes both bricks and the mortar in horizontal and vertical joints. Mortar volume is found by subtracting the brick volume from total masonry volume. Mortar therefore represents only part of the finished structure.
Why can reinforcement mesh length be several times the wall length?
Masonry reinforcement mesh is installed at multiple levels throughout the wall height rather than in one course. The calculated wall length is multiplied by the number of reinforcement levels. Mesh below windows is also counted, with 500 mm of extension on each side.
Why is the masonry area sometimes missing from the results?
If exterior walls, partitions or gables differ in thickness, their combined area does not describe a single uniform masonry section. The total area is therefore shown only when all sections have the same actual thickness. Masonry volume remains available because each thickness is accounted for separately.