Brick Quantity Calculator
Estimate how many bricks you need to cover a wall, dividing total wall area by the face area of one brick. Useful for ordering materials and getting a cost estimate before starting a masonry job.
Last updated: May 2026
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About this calculator
The formula is N = ⌈(L × H) / A⌉, where L is the wall length, H is the wall height (both in metres), and A is the face area of a single brick (including its mortar joint) in m². The ceiling function (⌈ ⌉) rounds up because you cannot order a fractional brick. The 'brickSize' selector pre-loads typical face areas: standard imperial brick (203×57 mm + 10 mm mortar joints) gives ~0.022 m²; UK metric brick (215×65 mm + 10 mm mortar) gives ~0.0169 m²; modular brick varies. The face area in the formula MUST include mortar joint thickness — a 'naked' brick is smaller than the spacing it occupies in a finished wall, so omitting the mortar would overestimate brick count by 15–25%. Variables: L = wall length, H = wall height, A = brick face area with mortar. Edge cases: this calculator assumes a single-leaf (single-thickness) wall; double-leaf walls (cavity walls) need 2× the count plus wall ties. It also assumes solid walls without windows, doors, or other openings — subtract the area of openings from L × H before dividing. Real masons add 5–10% extra for cutting, breakage, and pattern matching, especially for stretcher bond or running bond patterns at edges. For corners and pillars, brick patterns require headers and special pieces that the formula doesn't account for; consult brickwork pattern guides for accurate per-job adjustments.
How to use
Example 1 — Garden wall. A 5.0 m long × 1.8 m high single-leaf wall using UK metric brick (face area ≈ 0.0169 m² with mortar). Wall area = 5.0 × 1.8 = 9.0 m². Bricks = 9.0 / 0.0169 ≈ 532.5 → ceil(532.5) = 533 bricks. ✓ Order ~580 bricks (10% waste allowance) to cover cuts, breakage, and pattern losses at the ends. At ~£0.50/brick, that's ~£290 in materials. Example 2 — House extension with a window opening. Wall 8.0 m × 2.7 m, single-leaf, imperial brick (face area ≈ 0.022 m²), with a 1.2 m × 1.0 m window. Net wall area = (8.0 × 2.7) − (1.2 × 1.0) = 21.6 − 1.2 = 20.4 m². Bricks = 20.4 / 0.022 ≈ 928 → 928 bricks. ✓ Add ~10% waste → order ~1,020 bricks. Note: the calculator doesn't subtract the window opening for you — enter the effective wall area you actually want to brick.
Frequently asked questions
Should I include mortar joints when measuring brick size?
Yes — the relevant face area is the brick plus its mortar joint thickness on two sides (typically 10 mm). A UK metric brick is nominally 215 × 65 mm, but with a 10 mm mortar joint it occupies 225 × 75 mm = 16,875 mm² = 0.0169 m² in the wall. Using the bare brick face (215 × 65 = 13,975 mm² = 0.0140 m²) would overestimate the brick count by about 21%. Most brick datasheets give both 'work size' (with mortar) and 'co-ordinating size' (bare); use the work size for area calculations. Imperial brick conventions vary — US modular brick is nominally 7⅝ × 2¼ in with ⅜ in mortar joints, giving 8 × 2⅝ in face area. Always check the manufacturer's spec before computing.
How much wastage should I add for cuts and breakage?
5–10% is the rule of thumb. For a simple, straight, stretcher-bond wall with no complex features, 5% is enough — mostly cuts at the ends and occasional breakage in handling. For walls with corners, pillars, returns, and varied patterns (Flemish bond, English bond), waste can reach 10–15% because headers and corner blocks must be specifically sized. For arches, soldier courses, and decorative details, 15–20% waste is realistic. Round up to the nearest pack size (bricks are sold in packs of typically 400–500); ordering an extra pack costs ~£200 but eliminates the risk of running short mid-job, which means waiting days for another delivery and creating a clear seam between batches that often differ slightly in colour.
How do I calculate bricks for a cavity wall (two leaves)?
A cavity wall has two parallel brick leaves separated by a cavity (typically 50–100 mm) with insulation and tied together with wall ties. Each leaf is counted separately, so total bricks = 2 × (single-leaf count) for matched leaves. Many modern cavity walls use brick on the outer leaf and blockwork (larger blocks) on the inner leaf for thermal and cost reasons; in that case, calculate the outer brick count and use a separate block-count calculation for the inner leaf. Wall ties (roughly one per 0.45 m², or about 5/m²) are an additional ironmongery item not captured here. For cavity-wall projects, also calculate insulation and damp-proof course (DPC) materials separately.
What are the most common mistakes people make estimating brick counts?
The first is using the bare brick face area instead of the work size with mortar joints, overestimating count by ~20%. The second is forgetting to subtract openings (windows, doors) — for a typical residential wall that omission adds 100–300 unneeded bricks. The third is ignoring the second leaf in cavity walls, ordering half what's needed. The fourth is using metric brick face areas with imperial bricks or vice versa; the size mismatch can be 30%+ between conventions. The fifth is forgetting wastage altogether and ordering exactly the geometric count; running short mid-job means an emergency delivery and a visible colour seam in the finished wall. The sixth is ignoring complex features like corners and arches that consume more bricks than the simple area calculation suggests; sketch the bond pattern at key features before ordering. And the seventh is treating the result as exact — real masonry has natural variation.
When should I not use this calculator?
Skip it for stone masonry, concrete-block work, or other non-brick walls — each has its own dimensions and waste patterns. Avoid it for arches, vaults, or curved walls where the simple area-divided-by-face-area approach doesn't capture the geometry of complex courses. It is the wrong tool for restoration work where matching existing brick sizes (often nominally smaller than modern bricks due to historical conventions) matters more than total count; do a course-by-course takeoff instead. Do not use it for chimneys, pillars, or any structural element where load-bearing requirements dictate specific brick types and configurations beyond simple geometry. And for any large commercial or structural job, get a professional masonry takeoff — small calculator estimates are fine for planning but inadequate for ordering on multi-thousand-brick jobs where 5–10% error means thousands of pounds.