Brick Calculator
Enter your wall length and height, pick a brick size, and the calculator returns the number of bricks to order (including a waste allowance) and the total material cost — works for UK and US brick formats.
Bricks needed (with waste)
1,650
- Wall area (m²)
- 25
- Bricks per m² (this wall)
- 60
- Bricks before waste
- 1,500
- Total material cost
- £825.00
- Cost per m²
- £33.00
Bricks = wall area × bricks-per-m² × wall thickness, rounded up after waste. Bricks-per-m² comes from the brick face area plus the mortar joint on two sides: 1 / ((L + J) × (H + J)).
How to use this calculator
Measure the wall length and height in metres. If the wall has openings (windows, doors), calculate them separately and subtract their area from the wall area before ordering — the calculator treats the wall as a solid rectangle. Pick the brick size: UK modular (215 × 65 mm face with 10 mm joint) is the BS EN 771-1 standard sold by every UK merchant; US modular and US standard match the brick sizes catalogued by the Brick Industry Association. Select wall thickness — half-brick is a single-wythe garden wall or cladding (≈ 100 mm thick), one-brick is a load-bearing double-wythe wall (≈ 215 mm thick). Set a waste allowance (10 % is the merchant default — bump to 15 % if you are new to bricklaying or the design has lots of cuts), enter the unit price per brick, and the result panel shows the bricks to order, base count before waste, and total material cost.
How the calculation works
A brick is laid in a bed of mortar, so the area it occupies on the wall is bigger than its face. The Brick Industry Association formula (Technical Note 10) is bricks per unit area = 1 / ((L + J) × (H + J)) where L and H are the brick face dimensions and J is the mortar joint thickness. For UK modular brick (215 × 65 mm with 10 mm joint), that gives (225 × 75) = 16,875 mm² per brick, or 1,000,000 / 16,875 ≈ 59.26 bricks per m² — rounded by the Brick Development Association to the published 60 bricks per m² figure for a half-brick wall. A one-brick wall is two wythes stacked back-to-back, so the brick count doubles. The calculator multiplies wall area × bricks-per-m² × wall thickness factor, then rounds up after applying the waste percentage.
Worked example
A 10 m × 2.5 m garden wall in UK modular brick, single-wythe (half-brick), 10 % waste, £0.50 per brick. Wall area = 10 × 2.5 = 25 m². Bricks per m² = 60 × 1 (single wythe) = 60. Base bricks = 25 × 60 = 1,500. Add 10 % waste = 1,500 × 1.10 = 1,650 bricks to order. Total material cost = 1,650 × £0.50 = £825, or £33 per m². If the same wall were one-brick (double-wythe), the brick count would double to 3,300 and the cost to £1,650 — the doubling is the dominant cost driver, far more than the unit brick price.
Frequently asked questions
How many bricks are in a square metre of wall?
For a UK half-brick wall built with standard modular bricks (215 × 65 mm face, 10 mm mortar joint per BS EN 771-1), the Brick Development Association publishes 60 bricks per m². For a one-brick (double-wythe) wall, double it to 120 bricks per m². US modular brick (BIA Tech Note 10) gives 6.75 bricks per ft², or about 72.66 per m². If you are using a non-standard brick, divide 1,000,000 by (L + J) × (H + J) in millimetres to get the bricks-per-m² figure.
What does "half-brick" and "one-brick" wall mean?
Brick walls are described by the number of brick widths laid side-by-side through the wall thickness. A half-brick wall is one brick wide (its width is half the length of the brick laid in the standard "stretcher" orientation) — about 100 mm thick, used for non-loadbearing garden walls, cavity-wall outer leaves, and brick cladding. A one-brick wall is two bricks wide (216 mm thick), used for loadbearing solid walls, retaining walls, and freestanding garden walls over about 1.2 m high. The calculator multiplies the brick count by 1 for half-brick or 2 for one-brick — there is no extra mortar-joint adjustment because the cross-joints in a one-brick wall are stretcher bond, not extra material.
Why include a 10 % waste allowance?
Bricks crack on delivery, break during cutting at corners and openings, and the bond pattern (the way bricks overlap in adjacent courses) forces you to cut half-bricks and quarter-bricks that cannot be re-used. 10 % is the figure the major UK merchants (Wienerberger, Ibstock, Forterra) build into their order calculators for a straightforward straight wall. Bump it to 15 % if the design has lots of returns or openings, or if you are new to bricklaying. Sub-10 % is realistic only for an experienced bricklayer on a long uninterrupted run, and even then the unit price of running out part-way through a job (return delivery, mismatched batch, programme delay) is much higher than the cost of the extra 5 % of bricks.
Does the calculator include mortar, foundations, or wall ties?
No — it returns the brick count and brick cost only. As a rough rule, a half-brick wall needs roughly 0.022 m³ of mortar per m² of wall (about 60 kg of ready-mix mortar, or 1 bag of cement + 4 of building sand per 6–7 m²); a one-brick wall doubles it. Foundations, damp-proof course, wall ties (for cavity walls), and weep vents are all extras priced separately. For load-bearing or retaining walls always have a structural engineer specify the footing — the brick maths is the easy part; the foundation is where most amateur garden walls fail.
How accurate is the count for cavity walls?
A standard cavity wall has two leaves: a half-brick outer leaf and either a half-brick inner leaf or (more commonly) a blockwork inner leaf. To estimate the outer leaf bricks, use the calculator with wall thickness = half-brick. If both leaves are brick, run it twice (or use one-brick thickness, which gives the same total). The calculator does not estimate block counts for the inner leaf — concrete blocks are typically 440 × 215 mm face with 10 mm joint, giving 10 blocks per m², so use a dedicated block calculator for the inner leaf.
What about brick weight and pallet count?
A UK modular clay brick weighs about 2.5 kg, so the 1,650 bricks in the worked example weigh roughly 4.1 tonnes — too much for one delivery without proper access. Most merchants supply bricks on pallets of 400–500 bricks (one tonne each). For the worked example: ⌈1,650 / 500⌉ = 4 pallets. Check that your site has crane or HIAB access; otherwise specify "loose load" delivery, which costs more but lets the driver hand-stack on a normal driveway.