BuildCalcs Brick Calculator UK
Estimate how many bricks you need for a wall using its dimensions, openings, bricks per square metre, wall construction and waste allowance. Includes standard UK brickwork presets plus custom brick and joint sizes.
Reviewed: 20 September 2026 · How we check calculations
How many bricks do I need?
Enter the width and height of one wall, deduct the combined area of doors and windows, select the wall construction and choose how the bricks-per-square-metre rate should be determined. The calculator then adds your waste allowance and rounds the result up to a whole brick.
Brick calculator formula
For a single leaf, the basic calculation is net wall area × bricks per m². The wall construction multiplier is then applied, followed by the selected waste allowance. If you have several identical walls, the net area is multiplied by the number of walls before the brick quantity is calculated.
How many bricks per m²?
A widely used planning figure for a standard UK brick measuring about 215 × 65 mm with approximately 10 mm mortar joints is 60 bricks per m² for a half-brick-thick wall or single brick leaf. BuildCalcs uses 60/m² as the default because it is a familiar site-planning convention. If your bricks or joints differ, switch to the dimensions mode or enter your own rate.
| Wall construction | Typical planning rate | What the rate represents |
|---|---|---|
| Single leaf / half-brick wall | About 60 bricks/m² | One brick face per wall area |
| One-brick-thick solid wall | About 120 bricks/m² | Approximately two brick leaves in thickness |
| Cavity wall — outer brick leaf | About 60 bricks/m² | Facing-brick outer leaf only; inner leaf estimated separately |
Standard UK brick size and mortar joints
A commonly used UK brick size is 215 mm long × 102.5 mm wide × 65 mm high. For estimating the number visible in a square metre of wall, the relevant face dimensions are the brick length and height plus the mortar joints. With a nominal 10 mm joint, the face module is about 225 × 75 mm. The pure geometric rate is roughly 59.3 bricks/m², which is commonly rounded to 60 for planning.
Different brick sizes, bonds, joint profiles, specials and detailing can change the real quantity. The dimensions mode gives a geometric face-area estimate; it does not attempt to model every bond or special brick.
Worked example: 5 m × 2.4 m wall with a 2 m² opening
The gross wall area is 12 m². Deducting 2 m² of doors or windows leaves a net area of 10 m². At 60 standard bricks/m², that is 600 bricks before waste. With a 10% allowance, the planning quantity is 660 bricks.
More brick quantity examples
| Example | Net wall area | Rate used | Before waste | With 10% waste |
|---|---|---|---|---|
| 5 × 2.4 m wall, 2 m² openings | 10.0 m² | 60/m² | 600 | 660 |
| 8 × 2.4 m cavity-wall outer leaf, 4 m² openings | 15.2 m² | 60/m² | 912 | 1,004 |
| 4 × 2.4 m one-brick solid wall | 9.6 m² | 120/m² | 1,152 | 1,268 |
Allowing for doors and windows
Measure each opening's width and height, multiply them to get square metres, then add the opening areas together. Enter that total in the openings field. BuildCalcs deducts the opening area from each wall before applying the brick rate. Very small openings, returns, reveals, piers, arches and other details can affect the actual quantity, so treat the result as a materials estimate rather than a brick-by-brick setting-out plan.
Waste allowance and pack quantities
The default 10% allowance is adjustable. The amount you actually need depends on cuts, damage, brick matching, bond, detailing, transport and site conditions. If your supplier sells full packs, enter the pack quantity to see how many whole packs would cover the calculated requirement. Check whether opened or unused packs can be returned before ordering extra.
Estimating brick cost
If you have a supplier price per 1,000 bricks, enter it above and the calculator will estimate the brick-only material cost from the planning quantity. The estimate does not include mortar, blocks, wall ties, insulation, lintels, delivery, scaffolding, labour or other project costs.
Frequently asked questions
How many standard UK bricks are needed per square metre?
A common planning rate is about 60 standard bricks per m² for a single leaf or half-brick-thick wall when using 215 × 65 mm bricks with roughly 10 mm mortar joints.
How many bricks per m² for a one-brick-thick solid wall?
About 120 standard bricks per m² is a common planning figure because a one-brick-thick solid wall contains roughly twice as many bricks as a single leaf.
Does a cavity wall need 120 bricks per m²?
Not for the outer facing-brick leaf alone. A typical cavity wall outer leaf can be estimated at about 60 facing bricks/m². The inner leaf is often blockwork and should be estimated separately.
Why does the dimensions mode show about 59.3 instead of 60 bricks/m²?
Using a 215 × 65 mm brick with 10 mm nominal joints gives a geometric face module of 225 × 75 mm, or about 59.3 bricks/m². The conventional 60/m² figure is a practical rounded planning rate.
How do I allow for doors and windows?
Calculate the combined area of the openings in square metres and enter it in the openings field. The calculator deducts this from the wall area before calculating bricks.
What waste allowance should I use?
The calculator defaults to 10%, but there is no universal percentage. Cuts, breakage, matching, bond and site conditions can change the allowance, so use a figure appropriate to your project and supplier guidance.
Can I use non-standard bricks?
Yes. Select Calculate from brick + joint dimensions and enter the brick length, height and nominal joint thickness, or choose the custom-rate option if you already know the appropriate bricks-per-m² figure.
Does the brick calculator include mortar?
No. The main result is the brick quantity. Use the separate Mortar Calculator to estimate cement and sand for a specified mortar volume and mix ratio.