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Brick Calculator
Counts the bricks in a single-leaf (half-brick, stretcher-bond) wall from its length and height using a standard brick size with its mortar joint, adds waste, and estimates the mortar volume geometrically and the bags of mortar mix from a manufacturer rule of thumb.
When to use
You need the number of bricks and the mortar for a garden wall, veneer or single-skin wall of known face area.
Do not use when: The wall is concrete block (use the block face 440 × 215 mm or 8 × 16 in as a custom brick) or two leaves thick: double the brick count, or use concrete-slab for footings.
Formula
bricks_per_m² = 1 / ((L + j) × (H + j)); bricks = ceil(wall_area × bricks_per_m² × (1 + waste/100)); mortar_m³ = wall_area × W − wall_area × bricks_per_m² × L × W × H; bags_80lb = ceil(bricks / 37); bags_25kg = ceil(bricks / 25). US modular uses the nominal 8 × 2⅔ in course module (3 courses = 8 in).
Single-leaf stretcher bond only; the geometric mortar volume (≈ 0.018 m³ per m² for UK bricks, close to BIA's 5.5 ft³ per 100 ft² for modular brick) excludes frogs, perforations and dropped mortar, which is why bag counts use the manufacturer's per-brick rule instead.
Inputs
| Parameter | Type | Unit | Required | Description |
|---|---|---|---|---|
unit_system | enum: metric | imperial | default metric | Unit system of the length inputs (metric: m / cm / mm; imperial: ft / in). Outputs are reported in both systems. | |
wall_length | number | m or ft | yes | Length of the wall face (m or ft). Range: > 0, ≤ 10000 |
wall_height | number | m or ft | yes | Height of the wall face (m or ft). Range: > 0, ≤ 100 |
brick_size | enum: us_modular | uk_standard | au_standard | de_nf | metric_modular | custom | no | Brick format. Default uk_standard (metric) or us_modular (imperial). | |
brick_length | number | mm or in | no | Brick length for brick_size = custom (mm or in). Range: > 0, ≤ 1000 |
brick_height | number | mm or in | no | Brick height for custom (mm or in). Range: > 0, ≤ 1000 |
brick_width | number | mm or in | no | Brick width (wall thickness) for custom, used for the mortar volume (mm or in). Range: > 0, ≤ 1000 |
mortar_joint | number | mm or in | no | Joint thickness for custom bricks. Default 10 mm (metric) or 3/8 in (imperial). Range: ≥ 0, ≤ 50 |
waste_percent | number | % | default 5 | Extra material for cuts, breakage and offcuts, applied as a multiplier (1 + waste_percent/100). 5 % covers cut and broken bricks on plain walls; 10 % for walls with many openings or corners. Range: ≥ 0, ≤ 50 |
Outputs
| Output | Type | Unit | Description |
|---|---|---|---|
wall_area_m2 | number | m² | wall_length × wall_height. |
wall_area_ft2 | number | ft² | Wall face area in square feet. |
bricks_per_m2 | number | 1 / ((length + joint) × (height + joint)). | |
bricks_per_ft2 | number | Bricks per square foot. | |
bricks_needed_no_waste | integer | ceil(area × bricks_per_m²). | |
bricks_needed | integer | ceil(area × bricks_per_m² × (1 + waste_percent/100)). | |
mortar_volume_m3 | number | m³ | Geometric joint volume: area × brick_width − bricks × brick volume. |
mortar_volume_cubic_feet | number | ft³ | Same volume in cubic feet. |
mortar_bags_80lb | integer | ceil(bricks_no_waste / 37): QUIKRETE states one 80 lb (36 kg) bag lays up to 37 standard bricks, waste included. | |
mortar_bags_25kg | integer | ceil(bricks_no_waste / 25), the 80 lb figure pro-rated by bag mass. |
Example
20 ft × 8 ft wall, US modular brick, 5 % waste: {"unit_system":"imperial","wall_length":20,"wall_height":8,"brick_size":"us_modular","waste_percent":5} → {"wall_area_ft2":160,"wall_area_m2":14.86,"bricks_per_ft2":6.75,"bricks_per_m2":72.66,"bricks_needed_no_waste":1080,"bricks_needed":1134,"mortar_volume_cubic_feet":9.46,"mortar_volume_m3":0.268,"mortar_bags_80lb":30,"mortar_bags_25kg":44}
6 m × 2.4 m wall, UK standard brick, 5 % waste: {"unit_system":"metric","wall_length":6,"wall_height":2.4,"brick_size":"uk_standard","waste_percent":5} → {"wall_area_m2":14.4,"bricks_per_m2":59.26,"bricks_needed_no_waste":854,"bricks_needed":896,"mortar_volume_m3":0.254,"mortar_bags_80lb":24,"mortar_bags_25kg":35}
GET https://tttkmbb.com/api/v1/calculate/brick?unit_system=imperial&wall_length=20&wall_height=8&brick_size=us_modular&waste_percent=5
Machine access
- API:
GET https://tttkmbb.com/api/v1/calculate/brick(query parameters) orPOSTwith a JSON body{"inputs": {...}} - Schema: https://tttkmbb.com/api/v1/calculators/brick · Markdown: https://tttkmbb.com/construction/brick.md · JSON definition: https://tttkmbb.com/construction/brick.json
- MCP: server
https://tttkmbb.com/mcp, toolrun_calculator with calculator_id="brick" - OpenAPI operationId:
estimate_bricks_needed - Freshness:
static. Authentication: none. Rate limit: fair use (see rate limits).
Sources
FAQ
How many bricks per square metre?
About 60 for UK bricks (215 × 65 mm with 10 mm joints gives 59.3), 50 for Australian and German formats, 73 for US modular (6.75 per ft²) and 75 for the 190 × 57 mm metric modular brick, all for a single leaf in stretcher bond.
What about a full-brick (one-brick-thick) wall?
Double the brick count (≈ 120 per m² for UK bricks) and roughly triple the mortar, because the collar joint between the two leaves is also filled.
Why do the mortar volume and the bag count not match?
The volume is the net geometry of the joints; the bag rule (37 bricks per 80 lb bag) is the manufacturer's practical figure and includes frogs, perforations and spillage, which typically double the mortar actually used.
Related calculators
- Concrete Slab Calculator — Concrete for the footing under the wall.
- Rectangle Calculator — Area of a wall with openings to subtract.
- Gravel Calculator — Hardcore or sand under the footing.