The Builder’s ToolkitFree UK building calculators
Wall quantity + openings

Brick Calculator

Work out how many bricks you need for a wall. Enter the wall size, deduct doors and windows, choose the wall construction, check the brick and joint dimensions, then add only the extra allowance you want.

Brickwork and masonry measuring illustration

Build your brick quantity

The calculator starts with the measured wall area, calculates a brick rate from the brick face and nominal mortar joint, then shows the base quantity and your selected extra allowance separately.

1. Wall measurements

m
Total measured wall length.
m
Measured height of the brickwork.
m²
Add the area of meaningful openings together and enter the total once.

2. Brickwork assumptions

The two-face option approximately doubles the wall-area brick count. Bonding, returns, piers and details can alter the real take-off.
mm
215 mm is the common UK metric clay-brick work length.
mm
65 mm is the common UK metric clay-brick work height.
mm
The common starting value is 10 mm; replace it when the actual specification differs.

3. Extra ordering allowance

%
Starts at 0%. Choose an allowance that suits the job, brick selection, cuts, breakage and supplier guidance.

How the brick calculation works

First, the calculator finds the gross wall area from length × height and subtracts the door and window area. It then calculates how many brick faces fit into one square metre using the brick length and height plus the nominal mortar joint. For a one-brick wall quantity estimate, that face rate is doubled.

Net wall area = wall length × wall height − openings. Brick rate per face = 1 ÷ ((brick length + joint) × (brick height + joint)), with millimetres converted to metres. Base bricks = net area × rate × wall-construction multiplier. Final bricks = base quantity + your selected allowance, rounded up to a whole brick.
Common UK starting values

The most widely used UK clay-brick work size is 215 × 102.5 × 65 mm. Brick Development Association dimensional guidance uses a nominal 10 mm mortar joint when describing the coordinating size. The wall-area calculation uses the 215 mm length and 65 mm height because the 102.5 mm depth does not change the exposed brick face area in this simple quantity method. For more detail, see the UK brick size and bricks-per-square-metre reference.

Why the result is close to 60 bricks per m²

With a 215 mm long × 65 mm high brick face and a 10 mm joint, the coordinating face module is approximately 225 mm × 75 mm. That works out at about 59.3 bricks per m² for one brick face, which is why UK estimating guidance is commonly expressed as roughly 60 bricks per m² for a half-brick wall and roughly 120 for a one-brick wall. The calculator keeps the underlying dimensions visible rather than hard-coding those rounded figures.

Deduct doors and windows before adding an allowance

If a wall contains significant openings, add their areas together and enter the total in the openings box. The calculator subtracts them from gross wall area before it calculates the brick quantity. Small openings, reveals, returns, arches and detailed brickwork may need a project-specific take-off rather than a simple area deduction.

Choose your own extra brick allowance

There is no single percentage that suits every job, so the calculator starts at 0%. Breakage, cutting, colour or texture selection, complicated details, matching an existing wall and supplier pack quantities can all affect what you decide to order. Keep the base quantity visible, then add the allowance you are comfortable with after checking the actual brick and project requirements.

Quantity estimate only. This tool does not design the wall, choose a bond, verify structural adequacy, determine cavity construction, check Building Regulations or replace drawings and specifications. Confirm the wall build-up, brick product, bond/details and supplier pack quantity before purchasing.

Worked example

For a 6.0 m × 2.4 m wall with 2.0 m² of openings, the net brickwork area is 12.4 m². Using 215 × 65 mm brick faces with 10 mm joints gives about 59.3 bricks/m² for a half-brick wall, so the mathematical base is about 735 bricks before any user-selected extra allowance and whole-brick rounding.

Use the right Builder’s Toolkit page for the next question

Need the estimating method?

The Brick Quantity Guide explains the workflow from measurement to ordering checks without duplicating this calculator.

Need brick-size context?

Use the UK Brick Size & Bricks per Square Metre reference for dimensions and rate context.

Planning bricks and mortar together?

The Brick Wall Materials Estimator joins the brick and mortar workflow. For mortar quantity alone, use the Brick Mortar Calculator.

Frequently asked questions

How many bricks are in 1 m² of wall?

With the common 215 × 65 mm brick face and a nominal 10 mm joint, the calculated face rate is about 59.3 bricks/m², normally rounded in practical guidance to about 60 for one brick face. A basic one-brick/two-face quantity estimate is approximately double.

Does the calculator include mortar joints?

Yes. The brick rate is calculated from the brick face dimensions plus the nominal joint you enter. The default is 10 mm, but it is editable.

Does it subtract windows and doors?

Yes. Enter their combined area in square metres. The calculator deducts that area before calculating the base brick quantity and before applying your extra allowance.

Why does the allowance start at 0%?

Because cuts, breakage, selection and detailing vary by job. The tool does not silently prescribe a universal waste factor; you choose the percentage after considering the actual project and supplier advice.

What if I am using a non-standard or reclaimed brick?

Enter the actual brick face length and height and the intended nominal joint. For irregular reclaimed units, unusual bonds or detailed work, use the result as a planning estimate and make a project-specific take-off.