Brick Calculator
Find how many bricks a wall needs from its dimensions, accounting for mortar joints and breakage. Defaults to a standard brick with a 10 mm joint; adjustable for blocks and other sizes.
How to use this calculator
- Enter the wall length and height in metres.
- Enter your brick dimensions and mortar joint in mm (10 mm is standard).
- The result is for a single-leaf wall — double it for a full-thickness wall.
Formula used
Each brick's footprint in the wall includes one mortar joint on two sides. A standard 215×65 mm brick face with 10 mm joints occupies 225×75 mm = 0.0169 m², giving about 60 bricks per square metre for a single leaf.
Example calculation
A 5 m × 2.4 m wall (12 m²) in standard bricks with 10 mm joints: ~59 bricks/m² → 712 bricks. With 10% waste → 783 bricks.
For a full double-leaf wall, double it to ~1,566.
Counting bricks with mortar in mind
The mortar joint is what turns brick counting from a simple division into a slightly larger number: each brick effectively occupies its own size plus a joint, so the wall holds fewer bricks than the naive area/brick-size sum — but forgetting the joint entirely overcounts. The standard shorthand, ~60 bricks per square metre for a single leaf with standard UK bricks, comes straight from this math.
Two things catch people out: wall thickness (a single-leaf half-brick wall uses half the bricks of a full double-leaf wall) and colour batches. Bricks vary in shade between production runs, so ordering enough in one go — plus the waste allowance for breakage and cuts — avoids a patchwork repair later.
Why use this calculator?
- Includes mortar joints, which naive counting ignores.
- Adjustable for blocks and non-standard brick sizes.
- Waste allowance for breakage, cuts and shade matching.
Frequently asked questions
How many bricks per square metre?
About 60 for a single-leaf wall using standard UK bricks (215×65 mm face) with 10 mm joints. A full-brick double-leaf wall uses about 120 per m². Different brick sizes change this — the calculator adjusts.
Does the calculator include mortar?
It accounts for mortar joints when counting bricks (they take up space, so you need fewer bricks). It doesn't estimate mortar quantity — as a rough guide, one m² of single-leaf brickwork needs about 0.02 m³ of mortar.
Single or double wall — which do I need?
Single-leaf (half-brick) walls suit garden walls and partitions; structural and external house walls are usually double-leaf or cavity construction. This tool counts a single leaf, so double the figure for a full-thickness wall.