Short answer: with common red bricks (230×115×75 mm) and 10 mm mortar joints, one square metre of wall needs about 49 bricks for a 4.5 inch wall and 98 bricks for a 9 inch wall. Add 5% for breakage when you order.
The formula
Bricks per m² of wall face, for one brick thickness:
1 ÷ [(brick length + joint) × (brick height + joint)], with all sizes in metres.
For a 230×115×75 mm brick with a 10 mm joint:
- (0.230 + 0.010) × (0.075 + 0.010) = 0.240 × 0.085 = 0.0204 m²
- 1 ÷ 0.0204 = 49 bricks per m² for a 4.5 inch (half brick) wall
- A 9 inch wall is two bricks thick: 49 × 2 = 98 bricks per m²
Bricks per m² by brick size
| Brick size | 4.5 inch wall | 9 inch wall |
|---|---|---|
| 230×115×75 mm (common red brick) | 49 | 98 |
| 230×110×70 mm | 52 | 104 |
| 190×90×90 mm (modular, IS 1077) | 50 | 100 |
All figures use 10 mm joints and no wastage. Thicker joints mean fewer bricks and more mortar. With 12 mm joints, a 230×115×75 mm brick needs about 48 per m² instead of 49.
Worked examples
| Wall | Area | Thickness | Bricks (no wastage) | Order (+5%) |
|---|---|---|---|---|
| Garden wall, 10 m × 1 m | 10 m² | 4.5 inch | 490 | about 515 |
| Room walls, 4 m × 4 m room, 3 m high, one door (2.1 × 0.9 m) | 46 m² | 9 inch | 4,508 | about 4,735 |
| Boundary wall, 20 m × 1.8 m | 36 m² | 9 inch | 3,528 | about 3,705 |
For the room: four walls of 4 m × 3 m = 48 m², minus the door (1.9 m²) ≈ 46 m². In a real house, walls are shared between rooms, so measure each wall once.
Tips for an accurate count
- Measure your bricks. Lay ten bricks end to end, measure, and divide by ten. Bhatta bricks often differ from the nominal size.
- Deduct openings. Subtract every door and window before multiplying.
- Count pillars separately. Boundary wall pillars need extra bricks.
- Choose wastage by quality. 5% for good bricks, 8–10% if the load has many broken or under-burnt bricks.
Working in feet? See bricks in 1 square foot. Working by volume? See bricks in 1 cubic metre.
