Brick Calculator
Enter the wall’s length and height, the area of any doors or windows, the size of one brick and the mortar joint, and a waste allowance. The calculator counts the bricks that fill the wall face and rounds up to whole bricks.
Answer
You need
1,152bricks
1,152 bricks for 160 sq ft of wall, about 6.86 per sq ft.
- sq ft of wall
- 160
- bricks per sq ft
- 6.86
- bricks before waste
- 1,097.1
Check the work
Every line comes from the same calculation as the answer.
bricks = ⌈ wall area ÷ ((brick + joint) × (brick + joint)) × (1 + waste) ⌉
| wall area | 20 × 8 − 0 | 160 sq ft |
|---|---|---|
| per brick | (8 ÷ 12) × (2.625 ÷ 12) | 0.145833 sq ft |
| bricks | 160 ÷ 0.145833 | 1,097.1429 |
| with waste | ⌈ 1,097.1429 × (1 + 0.05) ⌉ | 1,152 |
How it works
Bricks are counted by the face they show in the wall. Each brick, together with the mortar around it, takes up a small rectangle of wall; dividing the wall area by that rectangle gives the number of bricks for one layer.
The mortar joint matters more than it looks. A standard modular brick is 7 5/8 by 2 1/4 inches, but laid with 3/8-inch joints it occupies 8 by 2 5/8 inches. In metric, a 215 by 65 mm brick with 10 mm joints occupies 225 by 75 mm. Leaving the joint out overstates the count by roughly a fifth.
A waste allowance covers bricks cut at corners and ends, and the few that arrive chipped. It is a planning choice you make; a plain wall needs less than one with many openings or a decorative bond.
Formula
bricks = ⌈ (length × height − openings) ÷ ((brick length + joint) × (brick height + joint)) × (1 + waste) ⌉
The wall area is divided by the face one brick occupies including mortar, the waste allowance is added and the count is rounded up to whole bricks.
Worked examples
- Try these numbers
Garden wall, 20 by 8 ft, modular bricks
- The wall is 20 × 8 = 160 sq ft.
- Each brick with joint is 8 × 2.625 in = 0.6667 × 0.2188 ft = 0.1458 sq ft.
- 160 ÷ 0.1458 = 1,097.1 bricks; with 5% waste, exactly 1,152.
Buy 1,152 bricks.
- Try these numbers
Metric wall, 5 by 2.4 m, 215 × 65 mm bricks
- The wall is 5 × 2.4 = 12 m².
- Each brick with joint is 0.225 × 0.075 = 0.016875 m², about 59 bricks per m².
- 12 ÷ 0.016875 = 711.1; with 5% waste 746.7, rounded up to 747.
Buy 747 bricks.
- Try these numbers
Wall with a doorway
- The wall is 4 × 2.5 = 10 m², less a 2 m² doorway: 8 m².
- A 190 × 90 mm brick with 10 mm joints occupies 0.2 × 0.1 = 0.02 m².
- 8 ÷ 0.02 = 400 bricks.
400 bricks before any allowance for cuts.
Inputs and results
- Wall length
- Length of the wall, in feet or metres.
- Wall height
- Height of brickwork, in the same unit.
- Openings
- Area of doors or windows in the wall, in square feet or square metres. 0 if none.
- Brick length
- Length of one brick, in inches or millimetres.
- Brick height
- Height of one brick as laid, in inches or millimetres.
- Mortar joint
- Thickness of mortar between bricks, in inches or millimetres.
- Waste allowance
- Extra bricks for cuts and breakage, as a percentage you choose.
- Wall area
- Length times height, less openings.
- Area per brick
- Brick length plus joint, times brick height plus joint.
- Bricks to buy
- Wall area divided by area per brick, with your allowance, rounded up.
When to use it
- Ordering bricks for a garden wall, planter or barbecue surround.
- Checking a builder’s brick quantity for a single-skin wall.
- Comparing how many bricks a metric brick needs against an imperial modular brick for the same wall.
Common mistakes
- Entering the brick size without the mortar joint, then adding the joint again in your head; enter them separately and the calculator adds them.
- Using the area of the whole elevation when a door or window will be left open; subtract openings in their own field.
- Mixing units: brick and joint are in inches or millimetres, while the wall is in feet or metres.
What it does not do
- It counts one layer of bricks. A double-skin or cavity wall needs the count for each layer.
- It does not estimate mortar, sand, cement, wall ties or lintels.
- It does not account for piers, returns or decorative patterns that change how bricks are cut.
Method and assumptions
Brick and joint sizes are converted to the wall’s unit (12 inches to the foot, 1,000 millimetres to the metre). The net wall area is divided by the area each brick occupies with one joint in each direction.
The waste allowance multiplies that count, and the result is rounded up to whole bricks after removing floating-point residue, so an exact count such as 1,152 is not reported as 1,153.
Assumptions
- The wall is one brick thick.
- Every brick sits in one joint width horizontally and vertically.
- Bricks are bought individually or in whole numbers.
Edge cases
- Openings equal to or larger than the wall leave nothing to build, so no answer is shown.
- A joint of 0 models dry-stacked bricks.
- Very thin bricks such as slips give large counts; check the size field is in inches or millimetres.
Sources and corrections
This calculator uses an elementary formula, so it needs no outside data source. The method, the rounding rules and how a reported error is corrected are set out in the site standards.
Result looks wrong?
Send the inputs you used and the answer you expected. Every report is checked against the formula and its tests, and confirmed errors are corrected in public.