🧱 Brick Calculator
By ToolNimba Editorial Team · Updated 2026-06-19
Defaults assume a standard US modular brick with an 8 x 2.25 inch face and a 3/8 inch mortar joint, which works out to about 6.55 bricks per square foot (the common rule of thumb of 7). This estimates a single-wythe (one brick thick) wall. The waste allowance covers cuts, breakage, and offcuts.
This brick calculator works out how many bricks you need to build a wall. Enter the wall length and height, confirm the brick face size and the mortar joint thickness, and the tool returns the wall area, how many bricks fit in each square foot, and the total brick count including a waste allowance. The defaults match a standard US modular brick (an 8 x 2.25 inch face with a 3/8 inch joint), which is the familiar rule of thumb of about 7 bricks per square foot.
What is the Brick Calculator?
Estimating bricks starts with two numbers: the area of the wall and the area each brick covers once it is laid. A brick never occupies just its bare face, because every brick carries a mortar joint on one side and along the top. So the space one brick takes up on the wall is the face length plus one joint, multiplied by the face height plus one joint. For a standard modular brick that is (8 + 0.375) x (2.25 + 0.375) = 8.375 x 2.625 = 21.98 square inches. Dividing 144 square inches (one square foot) by that figure gives about 6.55 bricks per square foot, which the trade usually rounds up to 7.
From there the count is straightforward. Multiply the wall length by the wall height to get the gross area in square feet, subtract the area of any doors or windows you are not bricking over, then multiply the net area by the bricks-per-square-foot figure. That is the bare number of whole bricks the wall face needs. This calculator assumes a single-wythe wall, meaning one brick thick (a half brick or 4 inch nominal thickness). A double-wythe or full brick thick wall uses roughly twice as many, so double the result if you are laying two leaves.
No real job uses exactly the calculated number. Bricks snap when cut to fit corners and openings, some arrive chipped, and offcuts rarely get reused. Masons therefore add a waste allowance, usually around 5 to 10 percent, so the order already includes a cushion. Buying a little extra up front is far cheaper and less disruptive than running short near the end and waiting on another delivery, and any sound leftovers are useful for future repairs that match the existing wall exactly.
When to use it
- Estimating how many bricks to order for a garden wall, retaining wall, or house extension.
- Pricing a masonry job by turning a wall size into a brick count a supplier can quote.
- Checking a builder or contractor estimate before you commit to an order.
- Adjusting for a non-standard brick size or a thicker mortar joint than the usual 3/8 inch.
How to use the Brick Calculator
- Enter the wall length and height in feet.
- Confirm or change the brick face size (default 8 x 2.25 inches) and the mortar joint (default 3/8 inch).
- Subtract the square footage of any doors or windows in the wall, if needed.
- Set a waste allowance percentage to cover cuts and breakage.
- Read off the total bricks needed, the wall area, and the bricks per square foot.
Formula & method
Worked examples
A 10 ft x 8 ft wall built with standard modular bricks (8 x 2.25 in face, 3/8 in joint) and a 10% waste allowance.
- Brick face with mortar = (8 + 0.375) x (2.25 + 0.375) = 8.375 x 2.625 = 21.98 sq in
- Bricks per sq ft = 144 ÷ 21.98 = 6.55
- Wall area = 10 x 8 = 80 sq ft
- Bare bricks = 80 x 6.55 = 524.0, round up to 525
- With waste = 524.0 x 1.10 = 576.4, round up to 577
Result: About 525 bricks bare, or 577 bricks including 10% waste
A 20 ft x 6 ft wall with a 21 sq ft door opening, standard brick, 5% waste.
- Bricks per sq ft = 6.55 (same standard brick)
- Gross area = 20 x 6 = 120 sq ft
- Net area = 120 − 21 = 99 sq ft
- Bare bricks = 99 x 6.55 = 648.5, round up to 649
- With waste = 648.5 x 1.05 = 680.9, round up to 681
Result: About 649 bricks bare, or 681 bricks including 5% waste
Common brick sizes and their bricks per square foot (with a 3/8 inch mortar joint)
| Brick type | Face size (in) | Bricks per sq ft |
|---|---|---|
| Modular (standard) | 8 x 2.25 | 6.55 |
| Engineer modular | 8 x 2.75 | 5.50 |
| Closure modular | 8 x 3.625 | 4.30 |
| Roman | 12 x 1.625 | 5.82 |
| Norman | 12 x 2.25 | 4.43 |
| Utility | 12 x 3.625 | 2.91 |
Estimated bricks for a single-wythe wall using a standard modular brick (with 10% waste)
| Wall size | Area (sq ft) | Bricks (bare) | Bricks (with 10% waste) |
|---|---|---|---|
| 10 ft x 8 ft | 80 | 525 | 577 |
| 20 ft x 6 ft | 120 | 787 | 865 |
| 15 ft x 10 ft | 150 | 983 | 1,081 |
| 30 ft x 8 ft | 240 | 1,573 | 1,730 |
Common mistakes to avoid
- Forgetting the mortar joint. A brick covers more wall than its bare face because of the mortar around it. Counting only the brick face (without the joint) overestimates the number you need by roughly 15 to 20 percent. Always size the brick by its face plus one joint.
- Ignoring wall thickness (wythes). This tool estimates a single-wythe wall, one brick thick. A double-wythe (full brick thick) wall needs about twice as many bricks, so double the count if you are laying two leaves.
- Not subtracting openings. Doors, windows, and vents do not get bricked over, so their area should be removed from the wall area. Skipping this can lead to ordering hundreds of unnecessary bricks on a large wall.
- Ordering zero spare. Cutting bricks to fit corners and openings breaks some, and a few arrive chipped. A 5 to 10 percent waste allowance avoids a costly second delivery for the last few bricks and leaves matching spares for repairs.
Glossary
- Mortar joint
- The layer of mortar between bricks. A 3/8 inch joint is standard in US modular brickwork.
- Wythe
- A continuous vertical thickness of masonry one brick wide. A single-wythe wall is one brick thick.
- Modular brick
- A standard US brick with an 8 x 2.25 inch face designed so that the brick plus joint fits a 4 inch grid.
- Course
- A single horizontal row of bricks laid in mortar across the length of a wall.
- Waste allowance
- Extra material added to an order, usually 5 to 10 percent, to cover cuts, breakage, and offcuts.
Frequently asked questions
How many bricks do I need per square foot?
For a standard US modular brick (an 8 x 2.25 inch face) with a 3/8 inch mortar joint, you need about 6.55 bricks per square foot of wall, which the trade rounds up to 7. The exact figure changes with the brick size and joint thickness, so this calculator computes it from the dimensions you enter.
Does this include the mortar joint?
Yes. The calculator sizes each brick as its face length plus one joint by its face height plus one joint, so the mortar around every brick is already accounted for. That is why the count is lower than dividing the wall area by the bare brick face alone.
Is this for a single or double thickness wall?
The estimate is for a single-wythe wall, meaning one brick thick (about a 4 inch nominal thickness). For a double-wythe or full brick thick wall, you need roughly twice as many bricks, so double the result the tool gives you.
How much waste should I add?
A waste allowance of 5 to 10 percent is typical. It covers bricks broken while cutting to fit corners and openings, chipped bricks in the delivery, and offcuts that cannot be reused. Add more for walls with lots of curves, angles, or openings.
What brick size should I use?
The default is a standard US modular brick at 8 x 2.25 inches, the most common size. If your supplier uses a different brick (engineer, queen, Roman, or utility, for example), enter its actual face length and height and the tool recalculates the bricks per square foot for you.
How do I work out the wall area?
Multiply the wall length by its height to get the gross area in square feet, then subtract the area of any doors, windows, or vents that will not be bricked over. The calculator does this when you enter the dimensions and the openings figure.