Brick Calculator
Calculate the number of bricks and bags of mortar needed for a wall. Supports single and double brick walls with standard or metric brick sizes.
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How to use this calculator
Brick face area includes the mortar joint (typically 10 mm). Double brick walls need 2× bricks. Add 5–10% for waste and cuts.
- 1
Enter the wall dimensions in metres and the brick dimensions in millimetres.
- 2
Select single (100 mm) or double (200 mm) brick wall.
- 3
Enter the number and size of any door or window openings to subtract.
Frequently asked questions
What exact formula does this brick calculator use?
It divides the net wall area by the area one brick occupies including its joint, then applies the skin multiplier and the waste allowance. The face area is (brick length + joint) × (brick height + joint), both converted to metres. Bricks needed = net area × bricks per m² × skins × (1 + waste%), rounded up to a whole brick. With the default 230 × 76 mm brick and 10 mm joint that is 48.4 bricks per m² per face.
What does the single versus double brick setting change?
It is a plain multiplier. Choosing double brick (200 mm) doubles both the brick count and the mortar volume. The tool does not model a bond pattern, header courses or a cavity, so a wall built in English or Flemish bond may use a different count than twice the single-skin figure.
How are doors and windows deducted?
Only one kind of opening is offered: number of openings × width × height is subtracted from the wall area, and the net area never drops below zero. For windows, or for openings of different sizes, add up their areas yourself and enter them as one equivalent opening. Lintels, reveals and the extra cutting around openings are not allowed for beyond your waste percentage.
How is the mortar figure worked out?
This tool uses a flat 0.022 m³ of mortar per m² of net wall per skin, then divides by 0.014 m³ per 25 kg bag and rounds up. The 0.022 does not change with brick size or joint thickness, so entering a 0 mm joint still returns mortar. Treat the bag count as a rough starting point and check the yield printed on your mortar product.
Why is my brick count a whole number but bricks per m² has a decimal?
Bricks per m² is shown to one decimal place for reference and excludes waste. The order quantity multiplies the unrounded value by area, skins and the waste factor, and only then rounds up, so the total can differ slightly from multiplying the displayed 48.4 by hand.
Does the waste percentage apply to mortar?
No. Waste is applied to the brick count only. The mortar volume is calculated from the net wall area before any waste, so add your own margin for mortar if you expect spillage or a thicker joint.
Can it handle gable ends, curved walls, piers or arches?
No. It treats the wall as one rectangle of length × height. For a gable end, split it into a rectangle and a triangle and add the two areas yourself; for piers, arches and curved work, increase the waste percentage and confirm the quantity with your supplier.
Does this tell me what wall thickness or strength I need?
No. It counts materials for a wall you have already specified. Wall thickness, structural capacity, damp-proofing and local building rules are outside what it can judge, and a qualified builder or engineer should confirm them.
Brick calculator — bricks and mortar bags for a wall
From wall area to brick count
Every brick in a wall carries a share of mortar, so the area it claims is slightly larger than its visible face. The calculator adds the joint thickness to both the brick length and the brick height, multiplies them to get the area per brick, and divides one square metre by that figure. For a 230 × 76 mm brick with a 10 mm joint the cell measures 240 × 86 mm, which works out to 48.4 bricks per square metre. That number is multiplied by the net wall area, by one or two skins, and by the waste factor, and the result is rounded up so you never order a fraction of a brick. Because rounding happens only at the end, small wall sections are not inflated by repeated rounding.
Worked examples
These three walls were run through the calculator with the inputs listed in the first column. The second wall includes one door opening at the tool’s default 0.9 × 2.1 m, and the third has a zero-millimetre joint to show the effect on bricks per square metre.
| Inputs | Net area | Bricks per m² | Bricks needed | Mortar bags |
|---|---|---|---|---|
| 5 × 2 m, 230 × 76 mm, 10 mm joint, single, 10% waste | 10.00 m² | 48.4 | 533 | 16 |
| 8 × 2.4 m, 230 × 76 mm, 10 mm joint, double, 1 door, 5% waste | 17.31 m² | 48.4 | 1,762 | 55 |
| 3 × 1 m, 230 × 76 mm, 0 mm joint, single, 0% waste | 3.00 m² | 57.2 | 172 | 5 |
Reading the second example
The 8 × 2.4 m wall has a gross area of 19.2 m². One door of 0.9 × 2.1 m removes 1.89 m², leaving 17.31 m². At 48.4 bricks per square metre that is about 839 bricks per skin, doubled for the second skin and increased by 5%, giving 1,762. The mortar side is 17.31 × 0.022 × 2 = 0.762 m³, and dividing by 0.014 m³ per bag gives 55 bags after rounding up. Seeing the intermediate numbers helps when your supplier quotes per thousand bricks and you want to cross-check the order.
Changing brick size and joint
Brick dimensions are entered in millimetres, so the same page works for any face size. A 215 × 65 mm face with a 10 mm joint gives 59.3 bricks per square metre, which is noticeably more than the 48.4 of the default brick, and a 6 × 2.5 m wall with one door and 10% waste needs 855 of them. Joint thickness matters more than it looks: removing the joint entirely lifts the default brick from 48.4 to 57.2 per square metre. Always enter the joint you actually intend to lay.
What the estimate leaves out
The tool counts bricks and a ballpark mortar quantity for a flat rectangular wall. It does not design the wall, choose a bond, size lintels or check strength, and the mortar constant is fixed regardless of joint width. Cutting around openings, damaged bricks and breakage vary by site, so the waste percentage is yours to set. Treat the output as a material estimate to compare against a supplier’s quote, and let a qualified builder confirm the construction details.
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →