How the brick calculation works
Each brick, together with half the joint around it, takes up a small rectangle of wall. Divide the wall area by that rectangle and you have the brick count.
- Net wall area = total wall area − doors and windows.
- Area per brick = (brick length + joint) × (brick height + joint).
- Bricks = net area ÷ area per brick, then add waste.
bricks per sq ft = 144 ÷ ((L + joint) × (H + joint)), with L, H and joint in inches
mortar per brick = ((L + j) × (H + j) − L × H) × brick depth
Worked example
A wall of 240 sq ft with one 3 × 7 ft door (21 sq ft) leaves 219 sq ft. US modular brick with 3/8 in joints works out at 6.86 bricks per sq ft, so the wall needs 1,502 bricks. With 5 percent extra, buy 1,578. The joints hold about 12.1 cu ft of mortar, which is roughly 41 bags of 80 lb premixed mortar.
Bricks per square foot and per square meter
| Brick | Joint | Per sq ft | Per m² |
|---|---|---|---|
| US modular | 3/8 in | 6.86 | 73.8 |
| US standard | 3/8 in | 6.55 | 70.5 |
| US utility | 3/8 in | 3 | 32.3 |
| Australian 230 × 76 mm | 10 mm | 4.5 | 48.4 |
| UK 215 × 65 mm | 10 mm | 5.51 | 59.3 |
These are for a single wythe, one brick thick, laid in running bond with the long face showing. A double wall takes twice as many. Patterns with headers (bricks turned end-out), such as Flemish or English bond, need more.
Joint size matters
A thicker joint means fewer bricks but more mortar. Going from 3/8 in to 1/2 in joints drops US modular brick from 6.86 to 6.44 per sq ft, about 6 percent fewer. Match the joint your brick was designed for; modular brick and most metric brick are sized for a 3/8 in or 10 mm joint.
About the mortar estimate
The calculator measures the volume of the bed and head joints, then converts to bags using a common rating of about 37 modular bricks per 80 lb bag of premixed mortar. That rating already allows for normal droppings, so the bag figure is higher than the joint volume alone suggests. For large jobs, masons usually mix masonry cement and sand on site instead of using premix; ask your supplier for the mix ratio and yield.
Which mortar?
In the US, Type N mortar is the usual general-purpose choice for above-grade walls and veneer. Type S is stronger and is commonly used below grade, in retaining walls and where higher strength is specified. Very hard mortar is not better for soft or old brick: the mortar should be weaker than the brick so cracks form in the joints, which are easy to repoint. Follow your brick maker's advice and local code.
Waste and ordering tips
- Allow 5 percent for straight walls and up to 10 percent for walls with many corners, openings or cuts.
- Buy all bricks from the same production batch where possible, because color can vary between runs. Blend from several pallets as you lay.
- Bricks are often sold by the pallet or cube. Ask how many are on one before you round your order.
- Remember sills, soldier courses and arches. Count them separately if they use a special shape.
Safety and code notes
Garden walls and brick veneer need a solid footing and, for veneer, wall ties to the structure behind. Tall freestanding walls can topple in high wind, so height and thickness limits apply; check local code before building anything over about 3 to 4 ft. Wear eye protection when cutting brick and control silica dust with water or a vacuum-equipped saw.
For a deeper look at counts by brick type, read how many bricks per square foot. Building with block instead? Use the concrete block calculator.
Frequently asked questions
How many bricks are in a square foot?
About 6.86 US modular bricks with 3/8 in joints, or 6.55 US standard bricks. Many published tables round modular brick to 6.75 per sq ft.
How many bricks per square meter?
About 48 Australian 230 × 76 mm bricks or about 59 to 60 UK 215 × 65 mm bricks with 10 mm joints, for a single-thickness wall.
How much mortar do I need for 1,000 bricks?
With US modular brick and 3/8 in joints, the joints hold about 8 cu ft of mortar per 1,000 bricks, before droppings and waste.
Should I subtract doors and windows?
Yes. Subtract the full opening area, then add back any special units such as sills or soldier courses separately.