Before you order bricks, it helps to know roughly how many you need. Order too few and work stops; order too many and money gets stuck in a pile at the site. This calculator estimates the bricks, cement and sand for a wall from its size, the brick you use and the mortar mix.
How to use the brick calculator
- Enter the wall length and height in feet.
- Choose the thickness: 9 inch for outer and load-bearing walls, 4.5 inch for partition walls.
- Choose the brick size and the mortar mix (cement : sand).
- Enter the wastage. 5% is common; use more if bricks are brittle or the site is far.
For doors and windows, subtract their area from the wall first, or calculate each wall part separately.
How it is calculated
Wall volume = length × height × thickness
Bricks = wall volume ÷ volume of one brick with 10 mm mortar
Wet mortar = wall volume − volume of the bricks themselves
Dry mortar = wet mortar × 1.33
Cement (bags) = dry mortar ÷ (1 + sand parts) × 1,440 kg ÷ 50 kg
Sand = dry mortar × sand parts ÷ (1 + sand parts)| Brick | Size | Bricks in 1 m³ of wall |
|---|---|---|
| Standard (conventional) | 230 × 110 × 75 mm (9 × 4.5 × 3 in) | about 408 |
| Modular | 190 × 90 × 90 mm | 500 |
Example
A wall 10 ft long, 10 ft high and 9 inches thick, with standard bricks, mortar 1 : 6 and 5% wastage:
- Wall volume: 10 × 10 × 0.75 = 75 cft (2.12 m³)
- Bricks: about 868, plus 5% = 911 bricks
- Cement: about 2.6 bags of 50 kg
- Sand: about 19.2 cft (0.54 m³)
The same wall 4.5 inches thick needs about 456 bricks.
Tips
- Use 1 : 6 mortar for 9 inch walls and a richer 1 : 4 for 4.5 inch walls, which are thinner and need more strength.
- Soak bricks in water before laying so they don't suck water out of the mortar.
- Real use varies with brick quality, joint thickness and the mason. Treat the result as an estimate and keep a small buffer.
FAQ
How many bricks are needed for 100 sq ft of wall?
For a 9 inch wall with standard bricks, about 870 to 910 bricks, depending on wastage. For a 4.5 inch wall, about half of that.
How many bricks are in one cubic metre?
About 500 modular bricks, or about 408 standard 9 × 4.5 × 3 inch bricks, including 10 mm mortar joints.
Why is dry mortar 1.33 times the wet volume?
Cement and sand shrink when water is added and pack into gaps, so you need about a third more dry material than the finished mortar volume.