What Is the Brick Calculator?
The Brick Calculator estimates how many bricks are needed to build a wall of a given length and height. It takes into account the size of the brick and the thickness of the mortar joints, subtracts any openings, and adds an allowance for breakage and cuts. It also estimates the number of bags of mortar mix needed to lay the bricks.
The calculator is suited to garden walls, veneer on a house, planters, pillars and barbecue surrounds. It counts bricks for a wall one brick thick, known as a single wythe. For a double-thickness wall, the quantity is doubled.
How the Calculator Works
A brick wall is a grid of bricks separated by mortar. Each brick, together with the mortar joint on one end and one bed, occupies a fixed module. For a standard modular brick with a 3/8 inch joint, the module is 8 inches long and 2 5/8 inches high.
The calculator multiplies the module length by the module height to get its face area in square inches. Dividing 144 by that figure gives the number of bricks per square foot.
It multiplies the wall length by the wall height for the area, subtracts any openings, and multiplies by bricks per square foot. Waste is added and the result is rounded up. Mortar is estimated at one 80 pound bag of premixed mortar per 36 bricks.
The Brick Formula
Wall area = Length × Height − Openings
Bricks per sq ft = 144 ÷ ((Brick length + Joint) × (Brick height + Joint))
Bricks = Wall area × Bricks per sq ft × (1 + Waste % ÷ 100), rounded up
Mortar bags = Bricks ÷ 36, rounded up
Bricks per square foot for common sizes
With a 3/8 inch joint:
- Modular (7 5/8 × 2 1/4 in): 6.86
- Queen (7 5/8 × 2 3/4 in): 5.76
- King (9 5/8 × 2 5/8 in): 4.8
- Standard (8 × 2 1/4 in): 6.55
- Utility (11 5/8 × 3 5/8 in): 3.0
Step-by-Step Explanation
- Measure the wall length and height in feet and multiply for the area.
- Subtract the area of any doors, windows or gates.
- Add the joint thickness to the brick length and to the brick height.
- Multiply those two figures, and divide 144 by the result.
- Multiply the wall area by the bricks per square foot.
- Add 10 percent for waste and round up.
- Divide by 36 for the number of 80 pound mortar bags.
Worked Example
A garden wall is 20 feet long and 6 feet high, built from modular bricks with 3/8 inch joints.
- Wall area: 20 × 6 = 120 square feet.
- Module: 8 × 2.625 = 21 square inches.
- Bricks per square foot: 144 ÷ 21 = 6.86.
- Net bricks: 120 × 6.86 = 823.
- With 10 percent waste: 905.1, so 906 bricks.
- Mortar: 906 ÷ 36 = 25.2, so 26 bags.
- Courses: 72 inches ÷ 2.625 = 27.4, so 28 courses.
Bricks are commonly sold in cubes of about 500. You would order two cubes and have a small surplus.
How to Use the Calculator
- Enter the wall length and height.
- Enter the brick length and height. Use actual dimensions, not nominal ones.
- Enter the mortar joint thickness. Three-eighths of an inch is standard.
- Set the waste allowance.
- Enter the total area of any openings.
- Press Calculate.
For more detail on mortar, including different bag sizes, use the Mortar Calculator. A brick wall needs a footing, which you can size with the Concrete Calculator. If the wall will be built from larger units, the Concrete Block Calculator applies. Brick laid flat as paving is covered by the Paver Calculator, and wall areas with gables or arches can be worked out with the Square Footage Calculator.
Practical Tips
- Order all the bricks at once from the same batch. Colour varies between firings.
- Blend bricks from several cubes as you work to avoid patches of colour.
- Build the corners first, a few courses high, then fill in between them along a string line.
- Check level and plumb every course at the start. Errors compound.
- Dampen very dry bricks in hot weather so they do not suck water out of the mortar too fast.
- Mix only as much mortar as you can use in about an hour.
- Tool the joints when the mortar is thumbprint hard for a weather-resistant finish.
- Cover fresh work if rain or frost is expected.
Common Mistakes
Ignoring the mortar joint. Leaving the joint out overstates the count by about 15 percent for modular brick.
Using nominal dimensions. A nominal 8 inch brick is actually 7 5/8 inches. The nominal size already includes the joint.
Forgetting the wall thickness. A freestanding garden wall is often two wythes thick, which doubles the bricks.
No waste allowance. Bricks chip in transit and are cut at ends and openings.
Skipping the footing. A brick wall needs a concrete footing wider than the wall and below the frost line.
Too little mortar. Running out mid-course leads to inconsistent batches and visible colour changes in the joints.
Brick Bonds
Running bond, where each course is offset by half a brick, is the most common pattern for single-wythe walls and veneer. Common or American bond adds a course of headers every fifth or sixth course to tie two wythes together. Flemish bond alternates headers and stretchers in each course. English bond alternates full courses of headers and stretchers. Bonds with headers use more bricks per square foot of wall face because headers show their short end.
Wall Thickness and Structure
Brick veneer on a house is a single wythe tied to the framing with metal ties, with an air gap behind it. A freestanding wall above about 2 feet should be two wythes thick or reinforced with piers at intervals of 8 to 10 feet. Retaining walls and tall walls need engineering. Check local codes for height limits and footing requirements.
Mortar Types
Type N mortar is a general-purpose mix for above-ground exterior and interior walls. Type S is stronger and is used below ground and for retaining walls. Type M is the strongest and is used for foundations and heavy loads. Type O is a soft mix for repointing old, soft brick. Premixed bags only need water.
Reclaimed Brick
Reclaimed bricks have character and suit garden walls and paths. They vary more in size than new bricks, so measure a sample of ten and use the average in the calculator. Expect more waste, around 15 percent, because some will be cracked or have old mortar that will not come off cleanly. Old soft bricks are not always frost resistant, so ask the supplier whether they are suitable for exposed work.
Piers, Caps and Details
A pier one and a half bricks square uses about four and a half bricks per course. Multiply by the number of courses for each pier and add the total to the wall count. A wall should finish with a coping or cap that sheds water, such as a row of bricks laid on edge, which takes about three bricks per foot of wall, or a precast concrete cap. Good detailing at the top is what keeps water out of the wall and the mortar sound.
Estimating Cost and Delivery
Bricks are priced per thousand or per piece, and face bricks vary widely in price with colour and texture. Multiply the count from the calculator by the unit price, then add mortar, wall ties for veneer, and any lintels over openings. Delivery is usually by pallet or cube with a truck-mounted crane, so check that the truck can reach the place where you want the bricks set down. Stack bricks on boards and cover them, because bricks that sit in wet soil can stain and take up salts that later show as white efflorescence on the wall.