Brick Calculator
Enter the wall length and height, subtract any doors and windows, and choose a brick size and mortar joint to see how many bricks to buy, with and without waste, plus a geometric mortar estimate. Units can be imperial or metric.
Last updated November 4, 2026
Total area to subtract
Typical 3/8 in or 10 mm
A typical allowance, edit as needed
Example: 0.5 ft³. Check your bag label
Result
1,152 bricks to order
Includes the waste allowance. Mortar is a geometric estimate for bed and head joints.
| Net wall area | 160 sq ft |
|---|---|
| Bricks per sq ft (one wythe) | 6.857 |
| Bricks, no waste | 1,098 |
| Bricks with 5% waste | 1,152 |
| Mortar (bed and head joints) | 8.847 ft³ |
| Mortar with waste | 9.289 ft³ |
A planning estimate. Actual brick sizes, bond pattern, cuts and joints vary, so confirm quantities with your supplier or mason.
Show the work
Formula: bricks = net area ÷ ((length + joint) x (height + joint)) x wythes; order = bricks x (1 + waste ÷ 100)
- Wall area: 20 x 8 = 160 sq ft; minus openings 0 = 160 sq ft.
- Brick face with joints: (7.625 + 0.375) x (2.25 + 0.375) = 21 in².
- Bricks per sq ft: 144 ÷ 21 = 6.857.
- Bricks: 160 x 6.857 x 1 wythe = 1,097.143, rounded up to 1,098.
- Waste: 1,097.143 x (1 + 5 ÷ 100) = 1,152, rounded up to 1,152.
- Mortar: bed and head joints only, 8.847 ft³; 9.289 ft³ with the same waste.
Result: 1,152 bricks to order
How the number of bricks is worked out
bricks per area = 1 ÷ ((brick length + joint) × (brick height + joint))
bricks = net area × bricks per area × wythes
order = bricks × (1 + waste ÷ 100)
Each brick sits in a small rectangle made of its own face plus one mortar joint along the side and one along the top. That rectangle is the brick length plus the joint, times the brick height plus the joint.
For a US modular brick of 7-5/8 by 2-1/4 inches with a 3/8 inch joint, the rectangle is 8 by 2.625 inches, or 21 square inches. A square foot is 144 square inches, so a square foot of wall holds 144 ÷ 21 = 6.857 bricks. A 20 ft by 8 ft wall is 160 square feet, which needs 160 × 6.857 = 1,097.14 bricks, rounded up to 1,098.
Waste is added on top. At 5 percent the same wall needs 1,097.14 × 1.05 = 1,152 bricks. The 5 percent is a typical starting allowance that you can change from 0 to 100.
See how we calculate for the formulas, sources and review schedule behind every calculator.
Also useful alongside this calculator: Square Footage Calculator, Length Converter and Percentage Calculator.
Doors, windows and the net wall area
Enter the total area of doors and windows, each worked out as width times height. It is subtracted from the wall length times its height, and openings as large as the wall are rejected.
A 20 ft by 8 ft wall with one 21 square foot opening has a net area of 139 square feet, about 910 bricks of the US standard size before waste. The wall is treated as a plain rectangle, so arches, gables, piers and corners are not modelled.
Single and double wythe walls
A wythe is one vertical layer of masonry. A double wythe wall has two layers side by side, so it needs twice as many bricks for the same face area. The 20 ft by 8 ft modular wall rises from 1,098 to 2,195 bricks, or 2,304 with 5 percent waste.
Mortar covers bed and head joints only, not the collar joint between wythes, ties or reinforcement.
Brick sizes and joint thickness
The presets are common nominal sizes, including the UK metric brick of 215 by 65 by 102.5 millimeters. Real products vary, so use Custom size if your brick differs.
A thicker joint means fewer bricks per area. Going from a 3/8 inch to a 1/2 inch joint changes the 20 ft by 8 ft wall from 1,098 bricks to 1,032, but mortar rises from 8.8 to 11.2 cubic feet.
Mortar volume and bags
Mortar is the space inside each brick envelope that the brick does not fill: (length + joint) × (height + joint) × depth minus length × height × depth. For the modular brick that is 13.93 cubic inches per brick, so the 20 ft by 8 ft wall holds about 8.85 cubic feet. The same waste percentage is applied to the mortar as an assumption.
The bag count appears only if you enter how much mortar one bag makes. The field suggests 0.5 cubic feet or 14 liters as an example only; use the yield printed on your bag.
How to use the Brick Calculator
- Choose imperial or metric units.
- Enter the wall length and height, and the total area of doors and windows.
- Pick a brick size or Custom, then enter the mortar joint and choose single or double wythe.
- Keep the 5 percent waste or change it, and optionally enter the mortar yield per bag.
- Read the bricks to order and the mortar volume, then use Copy, Print or Share.
Worked example
A wall 20 ft long and 8 ft high, built of US modular bricks with 3/8 inch joints in a single wythe, has 160 square feet of face. At 6.857 bricks per square foot it needs 1,097.14 bricks, rounded up to 1,098, or 1,152 with 5 percent waste. The mortar for the bed and head joints is about 8.85 cubic feet.
| Net wall area | Bricks, no waste | Bricks with waste | Mortar (cubic feet) |
|---|---|---|---|
| 100 sq ft | 686 | 720 | 5.53 |
| 160 sq ft | 1,098 | 1,152 | 8.85 |
| 200 sq ft | 1,372 | 1,440 | 11.06 |
| 300 sq ft | 2,058 | 2,160 | 16.59 |
Frequently asked questions
How many bricks do I need per square foot of wall?
With US modular bricks and 3/8 inch joints it is about 6.86 bricks per square foot for a single wythe. Other sizes and joints change it.
How much waste should I allow for bricks?
The calculator starts at 5 percent as a typical allowance for breakage and cuts. Use more for many cuts, complex shapes or inexperienced work.
Does the calculator include mortar bags?
Only if you enter a bag yield. It then divides the estimated mortar volume by that yield and rounds up to whole bags.
Can I use it for a veneer or garden wall?
Yes, for any wall laid in rectangular courses with a constant joint. It does not suit flat paving, which has different bedding.
Is this a structural or building design?
No. It estimates quantities only. Ties, foundations and wall thickness should follow local code and a qualified mason.