How to use the brick calculator
Brick and block quantities are one of the first things a client or contractor asks about once an elevation is drawn. Counting them by hand is slow and easy to get wrong, especially once windows, doors and a second leaf are involved. This calculator gets you from wall size to an order quantity and a mortar estimate in one step.
- Choose metric or imperial for the wall dimensions. Brick sizes are always entered in millimetres, the way most product data sheets give them.
- Enter the wall length and height, and the total area of windows, doors and other openings to subtract.
- Pick a brick or block. The size and joint fill in automatically; overwrite them with the product you are specifying.
- Set the wythes or leaves, the waste allowance for units, and the mortar allowance. Add a price per unit if you want a material cost.
The results show the net wall area, units per m² or ft², the exact count, the number to order with waste, the mortar volume and, if you entered a price, the cost.
Brick and mortar formulas
Net area = Length × Height − Openings
Units per area = 1 ÷ ((Brick length + Joint) × (Brick height + Joint))
Units = Net area × Units per area × Wythes
Order = Units × (1 + Waste)
Mortar = Units × ((L + j) × (H + j) − L × H) × Depth × (1 + Allowance)
Each brick "owns" one bed joint and one head joint, so its coursing size is the brick plus one joint in each direction. Mortar is the volume of that coursing block minus the brick itself, treating the brick as solid.
| Unit (actual size, joint) | Per m² | Per ft² |
|---|---|---|
| UK / EU brick 215 × 102.5 × 65 mm, 10 mm | 59.3 | 5.5 |
| US modular brick 7 5/8 × 3 5/8 × 2 1/4 in, 3/8 in | 73.8 | 6.9 |
| US standard brick 8 × 3 5/8 × 2 1/4 in, 3/8 in | 70.5 | 6.5 |
| Australian brick 230 × 110 × 76 mm, 10 mm | 48.4 | 4.5 |
| Metric block 440 × 100 × 215 mm, 10 mm | 9.9 | 0.92 |
| US CMU 15 5/8 × 7 5/8 × 7 5/8 in, 3/8 in | 12.1 | 1.12 |
Worked examples
A UK extension wall
A 12 m long, 2.4 m high outer leaf has two 1.2 × 1.2 m windows. The net area is 28.8 − 2.88 = 25.92 m². At 59.3 bricks per m², that is 1,536 bricks, or 1,613 with 5% waste. The joints come to about 0.46 m³ of mortar, or 0.57 m³ with the 25% allowance.
A US garden wall
A freestanding wall 30 ft long and 6 ft high, one wythe of modular brick with 3/8 inch joints, is 180 ft². At about 6.85 bricks per ft² the wall needs 1,234 bricks, so order 1,296 with 5% waste. Mortar is about 0.35 m³, or 12.4 ft³, with the allowance.
A blockwork partition
A 20 m long, 3 m high wall in 440 × 215 mm blocks with 10 mm joints is 60 m². At 9.88 blocks per m² it takes 593 blocks, or 623 with waste. With full mortar beds the joints use about 0.49 m³ including the allowance.
Who this calculator helps
- Architects checking masonry quantities and costs while elevations and openings are still changing.
- Quantity surveyors and estimators doing quick take-offs before a full bill of quantities.
- Contractors and bricklayers ordering bricks, blocks and mortar for a job.
- Homeowners and self-builders budgeting a garden wall, extension or barbecue area.
- Architecture students learning how brick coursing and joint sizes drive quantities.
Tips for brick and block estimates
- Measure each elevation separately and add them up; measure gables as triangles with the square footage calculator.
- Raise the waste to 10% or more for many openings, piers, corners, decorative bonds or reclaimed bricks.
- Hollow concrete blocks laid with face-shell bedding use less mortar than the full-bed figure shown; reduce the allowance or check with the supplier.
- Footings for brick walls are a separate order; size them with the concrete calculator, and get a full budget with the construction cost calculator.
- Order all the bricks for a visible wall from the same batch, since colour can vary between production runs.
Deciding between brick colours or a render finish? Upload a photo of the house and test facade options with Exterior Redesign.
