Brick Calculator
Estimate the number of bricks, mortar, cement and sand for a brick wall. Deduct doors and windows and add your own wastage allowance.
How the calculator works
- Net area:
wall length × wall height − openings - Bricks per unit area (half-brick wall):
1 ÷ ((brick length + joint) × (brick height + joint)). A one-brick wall doubles this. - Wall volume:
net area × wall thickness. Thickness is the brick width for a half-brick wall, or the brick length for a one-brick wall. - Wet mortar:
wall volume − volume of the bricks themselves - Dry mortar: wet mortar × 1.27, then split by the cement : sand ratio
Cement is converted to bags at 1,440 kg/m³ and 50 kg per bag, rounded up.
Worked example: 10 m × 3 m wall, 3.5 m² openings
- Net area: 10 × 3 − 3.5 = 26.5 m²
- Brick with joint: 200 × 100 mm = 0.02 m², so 50 bricks per m²
- Bricks (half-brick wall): 26.5 × 50 = 1,325, or about 1,391 with 5% wastage
- Wall volume: 26.5 × 0.09 = 2.385 m³
- Brick volume: 1,325 × 0.00154 m³ = 2.04 m³
- Wet mortar: about 0.34 m³, so dry mortar is about 0.43 m³
- For a 1:5 mix: cement 0.072 m³ (about 3 bags) and sand 0.36 m³
Bricks per square metre
| Brick size (mm) | Joint | Half-brick wall | One-brick wall |
|---|---|---|---|
| 190 × 90 × 90 (modular) | 10 mm | 50 | 100 |
| 190 × 90 × 70 | 10 mm | 62.5 | 125 |
| 230 × 110 × 70 (traditional) | 10 mm | 51 | 102 |
| 215 × 102.5 × 65 (UK) | 10 mm | 59 | 118 |
Frequently asked questions
How many bricks are in one square metre?
For a modular 190 × 90 × 90 mm brick with 10 mm joints, a half-brick wall takes about 50 bricks per m². The number changes with brick size, so enter your own dimensions.
How much wastage should I allow?
5% is typical for machine-made bricks. Use 8 to 10% for handmade or irregular bricks, or for walls with many corners and cut bricks.
Should I deduct windows and doors?
Yes, deduct the full area of openings larger than about 1 m². Smaller openings are often ignored in rough estimates. Lintels and sills need separate material.
What mortar mix should I use?
1:4 to 1:6 cement-sand mortar is typical for brickwork. Richer mixes such as 1:3 or 1:4 suit load-bearing or exposed walls. Follow the specification on your drawings.
Does this include plaster?
No. Plaster, paint and tile quantities need their own calculation based on the wall surface area.
