How many bricks do you need for a wall? The answer depends on the wall area, brick size, mortar joint, wall thickness and the size of doors and windows. A small difference in brick dimensions can change the final quantity by hundreds of bricks on a large project.
For a useful estimate, calculate the net wall area first, then determine how much wall surface one brick covers when the mortar joint is included. Add a sensible allowance for cutting, breakage and site waste before ordering.
Use the BuildersMeasures Brick Calculator to estimate the number of bricks needed for your wall.
Table of Contents
- What Determines Brick Quantity?
- Calculate the Wall Area
- Subtract Doors and Windows
- Measure the Brick Size
- Include the Mortar Joint
- Calculate Bricks Per Square Metre
- Worked Example
- Wall Thickness and Brick Orientation
- Calculate Bricks for Multiple Walls
- Add a Waste Allowance
- Quick Brick Quantity Reference
- Common Brick Quantity Mistakes
- Use the Brick Calculator
- Frequently Asked Questions
What Determines Brick Quantity?
Brick quantity is not based on wall area alone. The following measurements affect the estimate:
- Wall length
- Wall height
- Brick length, height and width
- Mortar joint thickness
- Wall thickness
- Door and window openings
- Brick laying pattern
- Waste and breakage
The brick dimensions and mortar joint are especially important. Two projects with the same wall area can require different numbers of bricks when they use different brick sizes.
Calculate the Wall Area
Start with the gross area of the wall.
For example, a wall measuring 8 m long and 3 m high has:
This is the gross area. Openings still need to be deducted.
Subtract Doors and Windows
Doors and windows reduce the amount of wall requiring brickwork. Calculate their areas and subtract them from the gross wall area.
Example
Suppose the 8 m × 3 m wall has one door measuring 0.9 m × 2.1 m and two windows measuring 1.2 m × 1.2 m.
Door area = 0.9 × 2.1 = 1.89 m²
Window area = 1.2 × 1.2 × 2 = 2.88 m²
Total openings = 1.89 + 2.88 = 4.77 m²
The net brickwork area is:
Use 19.23 m² when calculating the brick requirement for the main wall surface.
Measure the Brick Size
Brick dimensions determine how much wall surface each brick covers. Measure the brick face exposed on the wall, not the brick's depth.
For a standard stretcher bond, the exposed brick face consists of the brick length and brick height.
For example, suppose a brick measures:
Height = 65 mm
Convert the dimensions to metres:
65 mm = 0.065 m
The brick face area without the mortar joint is:
Brick face area = 0.013975 m²
Mortar joints need to be included for a more practical bricks-per-square-metre estimate.
Include the Mortar Joint
Bricks are not normally placed edge-to-edge. Mortar occupies the joints between them.
For an estimating calculation, add the mortar joint thickness to the brick's length and height.
Effective brick height = Brick height + Joint thickness
Suppose the mortar joint is 10 mm, or 0.010 m.
Effective height = 0.065 + 0.010 = 0.075 m
The approximate wall area represented by one brick and its surrounding mortar is:
Effective area = 0.016875 m²
This method gives a practical estimate for a regular stretcher-bond wall. Actual brick consumption varies with bond pattern, joint size, cuts and construction details.
Calculate Bricks Per Square Metre
Once the effective brick area is known, divide 1 m² by the effective area of one brick.
Using the previous example:
Bricks per m² ≈ 59.26
So the theoretical requirement is about 59 bricks per square metre.
For an actual project, round the calculated requirement and add a waste allowance rather than ordering a fractional number of bricks.
Worked Example: Estimate Bricks for a Wall
Now combine the measurements.
| Measurement | Value |
|---|---|
| Wall length | 8 m |
| Wall height | 3 m |
| Gross wall area | 24 m² |
| Total openings | 4.77 m² |
| Net brickwork area | 19.23 m² |
| Brick length | 215 mm |
| Brick height | 65 mm |
| Mortar joint | 10 mm |
| Approx. bricks per m² | 59.26 |
Now calculate the bricks:
Bricks required ≈ 1,139.9
Round the result to approximately 1,140 bricks before adding waste.
Add 5% Waste
Using a 5% allowance:
Waste-adjusted quantity = 1,197 bricks
A purchasing estimate would therefore be about 1,200 bricks, subject to the actual brick dimensions, bond, openings and site requirements.
Wall Thickness and Brick Orientation
Wall thickness changes how the bricks are arranged. A thicker wall does not always mean you should multiply a single-face brick count by a fixed number. The bond and construction method matter.
Common arrangements include:
- Half-brick or single-leaf walls
- Full-brick or thicker masonry walls
- Cavity walls
- Walls using different bonding patterns
The calculation above uses the exposed face of the brick for a regular wall surface. For a wall built with a different bond or orientation, calculate the brick requirement from the specified construction detail.
Calculate Bricks for Multiple Walls
For a building with several walls, calculate each wall separately when the dimensions or openings differ.
For example:
Wall 2 = 14.2 m²
Wall 3 = 21.7 m²
Wall 4 = 16.4 m²
Add the net areas after deducting the relevant openings:
Total brickwork area = 70.8 m²
If the selected brick and mortar combination requires about 59.26 bricks per square metre:
Brick quantity ≈ 4,197 bricks
Add the selected waste allowance after calculating the base quantity.
Add a Waste Allowance
Some bricks will break during transportation, cutting or installation. Others might have defects or become unsuitable for a visible section of wall.
A waste allowance helps cover these losses. The appropriate percentage depends on brick quality, handling, cutting requirements, wall design and site practice.
For a 5% allowance:
For a 10% allowance:
Do not treat one waste percentage as a universal construction rule. Use the allowance specified by the project estimator or contractor when one exists.
Quick Brick Quantity Reference
| Calculation | Formula |
|---|---|
| Gross wall area | Length × Height |
| Net wall area | Gross area − Openings |
| Effective brick length | Brick length + Joint |
| Effective brick height | Brick height + Joint |
| Effective brick area | Effective length × Effective height |
| Bricks per m² | 1 ÷ Effective brick area |
| Base brick quantity | Net area × Bricks per m² |
| Waste-adjusted quantity | Base quantity × (1 + Waste %) |
Common Brick Quantity Mistakes
Using brick dimensions without mortar joints
A calculation based only on the physical brick face ignores the space occupied by mortar. Include the joint when estimating regular brickwork.
Using a generic bricks-per-m² figure
Brick sizes differ. A bricks-per-square-metre figure from one project might not suit another project.
Ignoring wall openings
Large doors and windows can remove a significant amount of brickwork. Deduct them from the gross wall area.
Forgetting wall thickness
A thicker masonry wall uses a different arrangement from a single-leaf wall. Confirm the construction detail before calculating the quantity.
Adding waste twice
Apply the waste allowance once after calculating the base brick quantity. Do not add multiple unexplained allowances to the same estimate.
Ordering before checking the actual brick
Nominal dimensions are not always the same as the dimensions of the supplied product. Check the manufacturer's stated dimensions before placing a large order.
Use the BuildersMeasures Brick Calculator
For one simple wall, the manual calculation is straightforward. Larger projects involve several walls, different openings and multiple measurements.
The BuildersMeasures Brick Calculator gives you a faster way to work through the core calculation using your wall dimensions, brick size, mortar joint and waste allowance.
- Wall Area Calculator for wall surface measurements.
- Mortar Calculator for mortar material estimates.
- Block Quantity Calculator for concrete or masonry block estimates.
- Paint Calculator for estimating paint requirements after wall construction and finishing.
Frequently Asked Questions
How do I calculate how many bricks I need for a wall?
Calculate the net wall area after subtracting openings, determine the effective area covered by one brick and its mortar joint, then multiply the net wall area by the bricks required per square metre. Add a suitable waste allowance afterward.
How many bricks are needed per square metre?
The number depends on brick dimensions and mortar joint thickness. For example, a 215 mm × 65 mm brick with a 10 mm joint gives an estimated 59.26 bricks per square metre using the effective-area method.
Should I subtract doors and windows when calculating bricks?
Yes. Subtract the area of doors and windows from the gross wall area when estimating the main brickwork quantity. Separate brickwork around reveals and other details should be measured when required.
Does mortar joint size affect brick quantity?
Yes. A wider joint increases the effective area represented by each brick, which reduces the number of bricks required per square metre. The actual joint should match the project specification.
How much brick waste should I allow?
The appropriate allowance depends on brick quality, transport, cutting, wall design and site handling. A project-specific allowance is preferable to applying one percentage to every job.
Does a thicker wall require more bricks?
Yes, but the quantity depends on how the wall is constructed. A thicker wall might use a different brick arrangement or bond, so do not multiply a single-wall estimate by an arbitrary factor.
Do different brick sizes change the quantity?
Yes. Larger bricks generally cover more wall area per unit, while smaller bricks require more units for the same surface area.
Should I use the manufacturer's brick dimensions?
Yes. Use the actual or specified brick dimensions for the project. This produces a more relevant estimate than relying on a generic brick size.
Can I calculate bricks for several walls together?
Yes. Calculate the net area of each wall, add the areas when the same brick and construction method apply, then calculate the total brick requirement and add the selected waste allowance.