Knowing how many bricks you actually need prevents costly overages and avoids mid-project shortages that delay your build. Whether you're laying a new garden wall, building a garage, or tackling a full house exterior, the calculation comes down to wall area, brick size, and mortar joints—and getting it right saves time and money.
Calculate Total Wall Area
Start with basic measurements: height and length of each wall section in metres. Multiply these together to get square metres, then add all wall sections.
For example, a simple rectangular garage wall 6m wide × 2.5m high = 15 m². If you're building two walls of equal size, that's 30 m². Account for openings (doors, windows) by measuring their dimensions and subtracting from your total. A standard door opening is roughly 2.1m × 0.9m (subtract 1.9 m²); a window might be 1.2m × 1m (subtract 1.2 m²).
Example: 30 m² wall area minus 1.9 m² (door) minus 1.2 m² (window) = 26.9 m² of actual brickwork.
Brick Types and Coverage Rates
Different brick sizes and bonding patterns affect coverage differently. Here's what you're likely working with:
- Standard UK brick: 215mm × 102.5mm × 65mm. With 10mm mortar joints, one brick covers approximately 0.0089 m² (roughly 112 bricks per m²)
- Australian brick: 230mm × 110mm × 76mm. Coverage is about 0.0095 m² (roughly 105 bricks per m²)
- Facing brick (larger format): 290mm × 145mm × 75mm. Coverage about 0.0135 m² (roughly 74 bricks per m²)
Standard bonding patterns (English bond, Flemish bond) have minimal variation in brick count; the main difference is labour efficiency and aesthetics, not material quantity.
Step-by-Step Calculation
1. Note your wall area (completed in step one above).
2. Determine brick type by checking supplier specs or existing work you're matching.
3. Look up bricks per square metre for your brick size and mortar joint thickness (usually 10mm).
4. Multiply: Wall area × bricks per m² = total bricks needed.
Example calculation:
- Wall area: 26.9 m²
- Brick type: Standard UK brick (112 per m²)
- Total needed: 26.9 × 112 = 3,013 bricks
Always add 5–10% for waste, breakage, and cutting. In this case: 3,013 × 1.08 = 3,254 bricks as your final order quantity.
Mortar Estimations
Don't forget mortar—it's a separate purchase and easy to underestimate. A typical rule of thumb: you'll need roughly 1 cubic metre of mortar per 500 bricks laid (or about 3–4 bags per m² of wall, depending on joint thickness and brick porosity).
For the example above (3,254 bricks), you'd order approximately 6–7 cubic metres of mortar, or 180–210 standard 25kg bags. Check with your supplier; they often provide ready-mixed solutions by the tonne or pre-bagged quantities.
Account for Bond Pattern and Wall Thickness
Single-skin walls (one brick thick, roughly 100mm finished) require the calculation above. Double-skin cavity walls (two layers of brick with a 50mm air gap) need roughly double the material for the same square metres of external face area.
If you're laying a feature wall in Flemish bond using facing bricks, the calculation stays the same—the pattern doesn't change quantity, only the time and skill required.
Get a Second Opinion
When in doubt, contact a local brick supplier or masonry contractor. Most provide free estimates based on your wall dimensions and will account for local availability, colour matching, and delivery logistics. If you're comparing contractors, Mercoly helps you find and compare trusted brick and block laying providers in one place, making it easy to get multiple quotes and timelines.
Frequently Asked Questions
Q: What if I order too many bricks? Most suppliers allow returns for unused, undamaged stock within 14 days, though you may face a restocking fee of 5–15%. It's cheaper to order slightly under (5%) and make a small second order than to overstock significantly.
Q: Do I calculate differently for decorative or heritage bricks? No—the calculation method is identical; coverage rates are set by brick dimensions and mortar joint thickness. Heritage bricks may vary slightly in size, so confirm exact dimensions with your supplier and recalculate if needed.
Q: Can weather affect how many bricks I need? No, but weather affects laying pace and mortar curing. Cold weather slows drying and may require additives; hot, windy weather accelerates drying and may reduce mortar workability. Plan your timeline accordingly, but material quantity stays the same.
Get accurate quotes from experienced bricklayers on Mercoly today.