Brickcount / Calculation guide
Calculation guide
This is an area-based estimate for a single wall face or skin. It uses the dimensions you enter rather than assuming every brick has one standard size.
1. Measure the wall face and openings
Multiply wall length by wall height in metres. Add together the face areas of any doors or windows and subtract that total. For separate rectangular walls, either calculate them separately or add their net areas before choosing equivalent length and height inputs. Irregular outlines are easier to break into measured rectangles.
Net face area = gross area − combined opening area
The opening total cannot exceed the gross face area. An opening equal to the whole face produces a zero quantity. The tool does not add brick returns around openings, separate piers, corners or other three-dimensional details.
2. Include mortar joints in the repeating module
Enter the actual visible brick face length and height in millimetres, plus the joint thickness you plan to use. The calculator adds one joint to each module dimension.
Unrounded bricks = net face area ÷ module area
This models a repeating wall face. It is not a layout drawing and does not count individual end cuts or edge joints. Decorative bonds, unusually wide joints, different brick orientations and multi-skin walls can need a more detailed take-off.
Worked example: the default wall
A 6 m × 1.8 m face has 10.8 m² gross area. Subtract 1.2 m² of openings to get 9.6 m². A 230 mm × 76 mm face with 10 mm joints gives a module of 240 mm × 86 mm, or 0.02064 m².
9.6 ÷ 0.02064 = about 465.116 bricks before rounding. Without an allowance, round up to 466 whole bricks. With a user-selected 10% allowance, calculate 465.116 × 1.10 = 511.628 and round up to 512 bricks. The allowance is applied before rounding, so it does not compound an earlier whole-brick rounding.
3. Separate allowance from pack rounding
The allowance is an estimate you choose for cuts, breakage and spares. There is no automatic recommendation that one percentage fits every job. Use zero if you want only the basic repeating-module estimate.
Packs = round up (target ÷ bricks per pack)
Purchase quantity = packs × bricks per pack
Worked example: buying packs
If the target is 512 bricks and a supplier sells packs of 50, the estimate becomes 11 packs or 550 bricks. The result shows 38 extra bricks from pack rounding, separate from your chosen allowance. These 50-brick packs are an arithmetic example, not a claim about supplier packaging.
Worked example: a different brick face
For a 4 m × 2 m wall with no openings, use a 200 mm × 100 mm face with 10 mm joints. The module area is 0.21 × 0.11 = 0.0231 m². That gives approximately 346.320 bricks. At 5% extra, the target is 364. With packs of 100, the purchase estimate is 4 packs or 400 bricks.
4. Check what is outside the estimate
This calculator estimates quantity for one face. It does not establish wall design, structural adequacy, footing dimensions, reinforcement, tie spacing, moisture detailing, local approvals or suitability of a particular brick. It also does not estimate mortar volume or labour.
Use the actual wall detail and bond layout to check end cuts, corners, openings, lintel zones, piers and any second skin. Discuss purchasing and availability with your supplier before ordering; the calculator cannot know the exact pack quantities or breakage on a delivery.
Frequently asked questions
Why does a thicker joint reduce the count?
A larger repeating module covers more face area per brick, so the area method returns fewer bricks. This arithmetic does not recommend changing the joint thickness.
Can I set the pack size to zero?
Yes. Zero disables pack rounding. The main result is then the target quantity with your allowance. Pack sizes must otherwise be positive whole numbers.
Why is “with allowance” not simply the rounded base plus 10%?
The calculation keeps the unrounded area quantity through the allowance step, then rounds once. This avoids adding extra rounding before the final target is calculated.