Ordering too few bricks stops work on site; ordering too many wastes money. This guide shows how to calculate the number of bricks for a wall, how much cement and sand the mortar needs, and the standard brick sizes used in India – with a fully worked example for a 9-inch wall, the formulas contractors use, and tips to control wastage and cost.
Standard Brick Sizes in India
| Brick type | Actual size (mm) | Bricks per m³ (with 10 mm mortar) |
|---|---|---|
| Conventional red brick | 230 × 115 × 75 | about 392 |
| Modular brick (IS 1077) | 190 × 90 × 90 | 500 |
| Fly ash brick | 230 × 110 × 75 | about 408 |
The modular brick is designed so that with a 10 mm mortar joint it occupies exactly 200 × 100 × 100 mm, which makes the maths neat: 1 ÷ (0.2 × 0.1 × 0.1) = 500 bricks per cubic metre. Local red bricks vary in size, so measure a few from your supplier before estimating.
Brick Calculation Formula
- Volume of brickwork = length × height × thickness of the wall (minus openings).
- Volume of one brick with mortar = (length + joint) × (width + joint) × (height + joint).
- Number of bricks = volume of brickwork ÷ volume of one brick with mortar.
- Add wastage of about 5% (up to 10% for broken or poor-quality bricks).
Worked Example: 3 m × 3 m Wall, 9 Inches Thick
Wall: 3 m long, 3 m high, 230 mm (9 inch, one full brick) thick. Conventional bricks 230 × 115 × 75 mm with 10 mm joints.
- Volume of wall = 3 × 3 × 0.23 = 2.07 m³
- One brick with mortar = 0.24 × 0.125 × 0.085 = 0.00255 m³
- Bricks = 2.07 ÷ 0.00255 ≈ 812 bricks
- With 5% wastage ≈ 852 bricks
How to Calculate Cement and Sand for Brickwork
Mortar fills the joints between the bricks.
- Wet mortar = volume of wall − (number of bricks × volume of one brick without mortar) = 2.07 − 812 × (0.23 × 0.115 × 0.075) ≈ 0.460 m³.
- Dry mortar = wet mortar × 1.33 (to allow for voids and bulking of sand) ≈ 0.611 m³.
- For a 1:6 mix (cement : sand), cement = 0.611 ÷ 7 ≈ 0.0873 m³. One 50 kg bag is about 0.0347 m³, so cement ≈ 2.5 bags.
- Sand = 0.611 × 6 ÷ 7 ≈ 0.524 m³ ≈ 18.5 cubic feet.
For a stronger 1:4 mix on external or load-bearing walls, the same wall needs about 3.5 bags of cement and 0.489 m³ (about 17.3 cft) of sand.
Example in Feet: 10 ft × 10 ft Wall
Many builders measure in feet. A wall 10 ft long, 10 ft high and 9 inches (0.75 ft) thick has a volume of 75 cubic feet, or about 2.124 m³. At about 392 bricks per m³ that is roughly 833 bricks, or about 875 with 5% wastage. A quick site rule of thumb is about 11 bricks per cubic foot for conventional bricks.
9-Inch vs 4.5-Inch Walls
- 9-inch (230 mm) walls – one full brick thick; used for external and load-bearing walls. Mix 1:4 or 1:5 is common.
- 4.5-inch (115 mm) walls – half-brick thick; used for internal partition walls. They need roughly half the bricks per square foot and usually a 1:4 mix, because thin walls need stronger mortar. Long half-brick walls need reinforcement or vertical supports.
Deduct Doors and Windows
Subtract the area of every door, window and ventilator before calculating. A 10 ft × 10 ft wall with a 3 ft × 7 ft door has 100 − 21 = 79 sq ft of brickwork. Our brick calculator has a box to deduct openings automatically. Do not deduct small openings under about 0.1 m² – the extra bricks cover cutting waste around them.
Estimating the Cost of Brickwork
Once you know the quantities, multiply by local rates: bricks per piece, cement per bag and sand per cubic foot. Add labour, which is often quoted per square foot or per 1,000 bricks, and transport. Prices vary widely between cities and seasons, so get two or three quotes. The brick calculator's cost section lets you enter your local rates.
Controlling Wastage
- Order from a reliable kiln – well-burnt bricks break less.
- Stack bricks on firm, level ground near the work area.
- Soak clay bricks in water before laying so they do not absorb water from the mortar.
- Plan cuts at corners and openings in advance.
- Keep 3%–5% extra for future repairs and matching colour.
How to Check Brick Quality
Good bricks are uniform in size and colour, have sharp edges, give a clear ringing sound when struck together, and do not break when dropped from about 1 metre onto another brick. Scratching with a fingernail should not leave a mark. Soak a brick in water for 24 hours – good bricks absorb less than about 20% of their weight.
Cement and Sand for Plastering
After the brickwork, walls are usually plastered. A common method for estimating plaster materials is:
- Wet volume = wall area × plaster thickness. For 10 m² at 12 mm: 10 × 0.012 = 0.12 m³.
- Add about 20% to fill joints and uneven surfaces: 0.144 m³.
- Dry volume = wet volume × 1.27 ≈ 0.183 m³.
- For a 1:4 mix: cement = 0.183 ÷ 5 ≈ 0.0366 m³ ≈ 1.05 bags; sand ≈ 0.146 m³ ≈ 5.2 cubic feet.
Internal walls are often plastered 12 mm thick and external walls 15–20 mm, and ceilings 6–10 mm. Plaster both faces of a wall if both are exposed, so double the area.
Bricks vs AAC Blocks
AAC (autoclaved aerated concrete) blocks are a popular alternative to clay bricks in apartments and commercial buildings. A typical AAC block measures 600 × 200 mm with thicknesses from 100 to 200 mm, so one block replaces several bricks. They are about a third of the weight of clay brickwork, which reduces the load on the structure, offer better heat insulation, and use thin-bed jointing mortar, which saves cement and speeds up work. Clay bricks remain cheaper in many small towns, are easy to repair and handle local weather well. Your engineer or architect can recommend the right material for your project.
Bricks per Square Foot of Wall
For quick estimates, builders often use bricks per square foot of wall face. With conventional bricks and 10 mm joints, a 9-inch wall needs roughly 8.4 bricks per square foot and a 4.5-inch wall about 4.2 bricks per square foot. Multiply by the wall area after deducting openings, then add wastage.
Curing Brickwork
Fresh brickwork must be kept moist for at least 7 days so the cement in the mortar gains strength. Sprinkle water two or three times a day, especially in hot, dry weather. Poorly cured mortar cracks and crumbles, which can mean costly repairs later – so include curing time in your construction schedule.
Frequently Asked Questions
How many bricks are in 1 cubic metre?
About 500 modular bricks (190 × 90 × 90 mm) or about 392 conventional bricks (230 × 115 × 75 mm), allowing for 10 mm mortar joints, before wastage.
How many bricks are needed for a 10 ft × 10 ft wall?
About 833 conventional bricks for a 9-inch wall, or roughly 875 including 5% wastage.
How much cement is needed per 1,000 bricks?
For a 9-inch wall in 1:6 mortar, roughly 3 bags; in 1:4 mortar, about 4.3 bags. It depends on joint thickness and brick size.
What mortar ratio should I use for brickwork?
1:6 is common for internal 9-inch walls, 1:4 for external and load-bearing walls and for half-brick partition walls. Follow your engineer's specification.
Why multiply wet mortar by 1.33?
Dry cement and sand shrink in volume when water is added because fine particles fill the voids. The factor of about 1.33 converts the wet volume into the dry materials required.
How much wastage should I add?
About 5% for good-quality bricks and careful work, and up to 10% if bricks are poor quality or there are many cuts.
How many bricks are needed per square foot?
Roughly 8.4 conventional bricks per square foot of a 9-inch wall, and about 4.2 for a 4.5-inch wall, before wastage.
How much cement is needed for plastering 100 square feet?
About 1 bag of cement for 12 mm plaster in a 1:4 mix on roughly 100 square feet (about 9.3 m²), depending on surface quality and wastage.
How long should brickwork be cured?
Keep it moist for at least 7 days by sprinkling water two or three times a day, especially in hot and dry weather.
Disclaimer: Quantities are estimates for planning and purchasing. Actual requirements depend on brick size, joint thickness and site conditions. Structural walls should be designed and approved by a qualified engineer.