Brick calculator
Work out how many bricks, bags of cement and cubic feet of sand a brick wall needs: enter the wall length, height and thickness, the brick size, the mortar joint and the mortar mix.
How it's calculated
- Wall volume = length × height × thickness.
- One brick with its mortar joint = (length + joint) × (width + joint) × (height + joint).
- Number of bricks = wall volume ÷ volume of one brick with mortar; then add the wastage % and round up.
- Wet mortar = wall volume − number of bricks (without wastage) × volume of one brick without mortar.
- Dry mortar = wet mortar × 1.33.
- For a 1:S mix (S parts of sand to 1 of cement): cement volume = dry mortar ÷ (1 + S); sand = dry mortar × S ÷ (1 + S). Cement bags = cement volume ÷ 0.0347 m³ (one 50 kg bag).
- Sand in cubic feet = m³ × 35.3147.
These results are estimates. Openings are not deducted, and brick size, breakage and mortar use vary on site.
Guide
How the number of bricks is found
The wall volume is length × height × thickness. One brick with its mortar joint takes up (length + joint) × (width + joint) × (height + joint); for the usual 230 × 110 × 55 mm brick with a 10 mm joint that is 240 × 120 × 65 mm, or 0.001872 m³. Dividing the wall volume by this gives the number of bricks, and the wastage allowance is added on top and rounded up.
Use 110 mm for a half-brick wall (bricks laid as stretchers, common for partitions) and 230 mm for a one-brick wall (bricks laid across the wall, common for outer walls).
Cement and sand for the mortar
The mortar is the wall volume minus the volume of the bricks themselves. Dry cement and sand take up about 1.33 times the wet mortar volume. In a 1:6 mix the dry volume is split in 7 parts, 1 of cement and 6 of sand. A 50 kg bag of cement is about 0.0347 m³, which gives the number of bags; the sand is shown in m³ and in cubic feet, the unit most suppliers use.
A 1:4 mix is richer and used for load-bearing and outer walls, and 1:6 is common for partition walls.
Limits
Results are estimates. Openings for doors and windows are not subtracted, so measure them separately and deduct them if you want a closer figure. Local bricks vary in size and breakage, and the real mortar use depends on how the mason works, so keep a wastage of about 5 % and order a little extra.
Frequently asked questions
How many bricks are needed for 100 sq ft of wall?
For a 230 mm thick wall with a 230 × 110 × 55 mm brick and 10 mm joints, about 123 bricks per square metre of wall face, so roughly 1,140 for 100 sq ft; for a 110 mm half-brick wall about half of that. Enter the wall size to get the exact count with wastage.
What size is a standard brick in Nepal?
The calculator starts with 230 × 110 × 55 mm, a common size. Local brick sizes vary, so measure the bricks you will buy and edit the three size fields.
Should I subtract doors and windows?
Yes, for a closer estimate: calculate the full wall, then calculate each opening as a separate wall with the same thickness and subtract its result.
