Brick Quantity Calculator
Find out exactly how many bricks you need to build a wall by entering its dimensions and your brick size. Useful for planning materials and budgeting before a build.
About this calculator
The number of bricks required for a wall is determined by dividing the total wall area by the face area of a single brick, then rounding up to the nearest whole brick. The formula is: Bricks = ⌈(wallLength × wallHeight) / brickSize⌉, where brickSize represents the face area of one brick (in m²) including the mortar joint. A standard metric brick with a 10 mm mortar joint has a face area of roughly 0.0222 m² (225 mm × 112.5 mm = 0.225 × 0.1125). Because bricks are always purchased in whole units and some breakage is inevitable, rounding up (ceiling function) is essential. Most builders also add a 5–10% wastage allowance on top of the calculated quantity to account for cuts, breakage, and matching future repairs.
How to use
Imagine building a garden wall 5 m long and 1.2 m high using standard metric bricks with a face area of 0.0222 m². Step 1 — Enter Wall Length = 5 m. Step 2 — Enter Wall Height = 1.2 m. Step 3 — Enter Brick Size = 0.0222 m². Step 4 — Wall area = 5 × 1.2 = 6 m². Step 5 — Bricks = ⌈6 / 0.0222⌉ = ⌈270.27⌉ = 271 bricks. Add 10% for wastage: 271 × 1.10 ≈ 298 bricks. Order 300 bricks to have a comfortable buffer.
Frequently asked questions
What is the standard brick size I should enter into the calculator?
The input expects the face area of one brick including its mortar joint, expressed in m². For a standard UK metric brick (215 mm × 102.5 mm) with a 10 mm mortar joint, the effective face dimensions become 225 mm × 112.5 mm, giving a face area of 0.0253 m². Australian standard bricks (230 mm × 76 mm) with a 10 mm joint yield 0.0242 m². Always add the mortar joint to both dimensions before calculating the face area.
How much wastage should I add when ordering bricks for a wall?
Industry guidance recommends adding 5% wastage for straightforward rectangular walls with few cuts. For walls with many window or door openings, or decorative patterns such as herringbone or diagonal, allow 10–15% because more cuts are required. It is far cheaper to order slightly too many bricks from the same batch than to source matching bricks later, as colour and texture can vary between firings.
How do I account for door and window openings when calculating brick quantity?
Calculate the total wall area as if the openings did not exist, then subtract the area of each opening (width × height) before dividing by the brick face area. For example, a 5 m × 2.5 m wall with one 1.2 m × 2.1 m door opening has a net area of (5 × 2.5) − (1.2 × 2.1) = 12.5 − 2.52 = 9.98 m². Divide that by your brick face area to get the adjusted brick count, then apply a wastage factor.