Short answer: with common red bricks (230×115×75 mm) and 10 mm mortar joints you need about 4.6 bricks per sq ft for a 4.5 inch wall and 9.1 bricks per sq ft for a 9 inch wall. Add 5% for breakage when you order.
On site, people round these to 4.5 and 9. That is fine for a rough estimate. For a full house it under-orders by a few hundred bricks, so use the exact figure when you place the order.
Bricks per sq ft, by wall and brick size
| Brick size | 4.5 inch wall | 9 inch wall | 13.5 inch wall |
|---|---|---|---|
| 230×115×75 mm (common red brick) | 4.6 | 9.1 | 13.7 |
| 230×110×70 mm | 4.8 | 9.7 | 14.5 |
| 190×90×90 mm (modular, IS 1077) | 4.7 | 9.3 | 13.9 |
These are without wastage. A 9 inch wall is two bricks thick, so it needs twice the bricks of a 4.5 inch wall. A 13.5 inch wall needs three times as many.
How the number is worked out
Take the face of one brick as it sits in the wall, and add the 10 mm mortar joint to its length and height:
- Brick face with joint: 240 mm × 85 mm = 0.0204 m²
- 1 sq ft = 0.0929 m²
- 0.0929 ÷ 0.0204 = 4.55 bricks per sq ft for one brick thickness (4.5 inch wall)
- A 9 inch wall has two layers: 4.55 × 2 = 9.1 bricks per sq ft
Bricks from bhattas vary in size. Before you calculate, lay 10 bricks end to end, measure the total and divide by 10. Do the same for height. If your bricks are 225 mm long instead of 230 mm, the count goes up by about 2%.
Worked examples
Room partition: 15 ft × 10 ft, 4.5 inch wall, one door
- Wall area: 15 × 10 = 150 sq ft
- Door (3 × 7 ft): 21 sq ft, so net area = 129 sq ft
- 129 × 4.55 = 587 bricks
- With 5% wastage: about 620 bricks
Outer wall: 40 ft × 10 ft, 9 inch wall, two windows
- Wall area: 40 × 10 = 400 sq ft
- Two windows (4 × 4 ft): 32 sq ft, so net area = 368 sq ft
- 368 × 9.1 = 3,349 bricks
- With 5% wastage: about 3,520 bricks
Boundary wall: 50 ft × 6 ft, 9 inch wall
- Wall area: 300 sq ft, no openings
- 300 × 9.1 = 2,730 bricks
- With 5% wastage: about 2,870 bricks
A boundary wall also needs a footing and usually pillars every 8 to 10 ft. Count the pillar bricks separately.
Do 3, 8 or 10 hole bricks change the count?
No. The count depends on the outer size of the brick, not the holes. A 230×110×70 mm perforated brick needs the same number per sq ft as a solid brick of that size. Perforated bricks do use a little more mortar, because some of it goes into the holes. See 3 hole bricks for more.
How much wastage to add
- 5% for good, well-burnt bricks and straight walls
- 8–10% if the load has many broken or under-burnt bricks, or the walls have many corners and cuts
Check a few bricks from every truck. A well-burnt brick is an even red colour, gives a clear ringing sound when two are struck together, and does not break when dropped flat from about 1 m onto hard ground.
