How to Use This Brick Calculator
Enter the wall width and height, pick your unit, choose a brick type and set the mortar joint thickness (⅜″ is the default). Subtract door and window openings, choose how many wythes thick the wall is, and slide the waste allowance to suit the job. You get the number of bricks to order, the 60-lb mortar bags to buy, bricks per square foot, a full breakdown, and an optional cost estimate.
Why This Matters
Ordering the right number of bricks before you start saves money and grief. Run short halfway up a wall and you may wait days for a delivery, only to find the new lot is a slightly different colour, because brick is fired in batches and shades vary. Over-order and you pay for hundreds of bricks you will never lay.
Take a 20 ft × 4 ft wall face in modular brick with ⅜″ joints. That is 80 sq ft, about 549 bricks laid, and 604 once you add 10% for cuts and breakage. A bigger job such as a 40 ft × 8 ft wall is 320 sq ft and needs about 2,195 bricks laid and 2,415 to order. Ordering a round 2,200 would leave you more than 200 bricks short. Mortar is forgotten just as often: that larger wall takes roughly 50 bags of 60-lb mix, and running out mid-course means rushed trips and weak joints. Homeowners planning a veneer, planter or garden wall, and contractors pricing a bid, need the same three numbers: bricks, mortar and cost.
How It's Calculated
All brick dimensions are in inches, and every wall dimension is converted to feet and square feet first. The calculator works from the brick plus one mortar joint (the “face cell”), then sizes mortar by volume.
Face cell (sq in) = (L + joint) × (H + joint)
Bricks per sq ft = 144 ÷ face cell
Net bricks = ⌈ area × bricks per sq ft × wythes ⌉
Bricks to order = ⌈ net × (1 + waste %) ⌉
Mortar per brick (cu in) = depth × [ (L + joint)(H + joint) − L × H ]
Collar joint (cu in) = area × 144 × joint × (wythes − 1)
Mortar (cu ft) = (net × mortar per brick + collar) ÷ 1,728 × (1 + mortar allowance)
Bags = ⌈ mortar ÷ yield per bag ⌉
Mortar is sized by volume rather than a square-foot coverage figure because a brick wall is thick: the bed and head joints around each brick hold real volume. A 60-lb bag of mortar mix yields roughly 0.45 cu ft, enough to lay about 40 to 45 modular bricks after waste. The default 25% allowance covers droppings, furrowing and mixing loss. The result is a geometry-based planning figure, and actual usage varies with mason skill and brick texture. Wythe count multiplies the brick total, and a collar joint equal to the joint thickness is assumed between wythes. All counts round up, never down.
Worked Example
A 20 ft × 4 ft wall in modular brick (7.625 × 2.25 × 3.625 in), ⅜″ joints, single wythe, no openings, 10% waste, $0.65 per brick and $7.50 per bag. These are the tool's defaults for those inputs:
- Wall area: 20 × 4 = 80 sq ft (11,520 sq in).
- Face cell: (7.625 + 0.375) × (2.25 + 0.375) = 8 × 2.625 = 21 sq in, which is 144 ÷ 21 = 6.86 bricks per sq ft.
- Net bricks: 11,520 ÷ 21 = 548.6, rounded up to 549.
- With 10% waste: 549 × 1.10 = 603.9, rounded up to 604 bricks.
- Mortar per brick: 3.625 × (21 − 7.625 × 2.25) = 3.625 × 3.844 = 13.93 cu in = 0.00806 cu ft. For 549 bricks that is 4.43 cu ft; with the 25% allowance, 5.53 cu ft.
- Bags: 5.53 ÷ 0.45 = 12.3, rounded up to 13 bags (780 lb), about 42 bricks laid per bag.
- Cost: 604 × $0.65 = $392.60; 13 × $7.50 = $97.50; materials total $490.10.
The calculator will also flag that a 4 ft single-wythe wall is very slender. That is fine for a veneer fixed to a structure, but not for a wall standing on its own.
Tips & Common Mistakes
- Always include waste. 5–10% suits simple running bond; use 15–20% for diagonal or herringbone patterns, lots of corners, or brittle used brick.
- Subtract openings. A 3 ft × 6.8 ft door is 20.4 sq ft, which is about 140 fewer modular bricks. Leave a little extra for the cuts around frames and lintels.
- Use actual brick sizes, not nominal. A “4 × 8” brick is really 3⅝ × 7⅝ in. Check the supplier's data sheet, and enter a custom size if it differs.
- Buy it all from one lot. Order a few percent over and keep spares for repairs, since colours drift between production runs.
- Mind height versus thickness. Unreinforced freestanding walls are commonly kept to roughly 4–6 times their thickness (a rule of thumb that depends on wind exposure), so a 3⅝″ single wythe is only about 1–2 ft high without piers or reinforcement. Taller, retaining and load-bearing walls need a design to local code.
- Use the right mortar. ASTM C270 Type N is typical above grade; Type S is common below grade and for stronger requirements. Follow your plans and local code.
Frequently Asked Questions
How many bricks do I need per square foot?
Modular bricks (7⅝″ × 2¼″) with ⅜″ joints need about 6.86 bricks per square foot of single-wythe wall. Standard 8″ bricks need about 6.55, Norman bricks about 4.57, and utility bricks about 3. The calculator works out the exact figure from your brick and joint size.
How much mortar do I need for 1,000 bricks?
For 1,000 modular bricks with ⅜″ joints, the joints hold about 8 cu ft of mortar. With a 25% allowance for waste that is about 10 cu ft, or roughly 22–23 bags of 60-lb mix at 0.45 cu ft per bag. That works out to about 43 bricks per bag, and the calculator uses the same method.
What is a wythe in brick construction?
A wythe is one vertical layer of masonry, one brick thick. A single wythe of modular brick is 3⅝″ thick, and a double wythe is about 7⅝″ to 8″ with a collar joint between the layers. Walls that carry load or stand free generally need more than a single unreinforced wythe, so confirm with your local code.
How much waste should I allow when ordering bricks?
Plan on 5–10% for straightforward running bond and 15–20% for complex patterns, curved work or many openings. Extra bricks are also useful for later repairs. The slider lets you compare totals, and the results include a table of order quantities for each waste level.
Does this include foundation or below-grade courses?
It estimates whatever wall area you enter, so run foundation courses as a separate calculation. Below-grade masonry often uses different units and Type S mortar, and it must meet footing and frost-depth requirements in your local code. Do not assume the above-grade wall design applies below ground.
Why does my supplier's number differ from the calculator?
Suppliers often round to full packs or cubes, and they use their own rules of thumb for waste and mortar. Joint thickness and brick size also change the count noticeably. Use the calculator to sanity-check the quote, then round up to whole packs.