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Construction & Home
Brick Calculator — How Many Bricks per Square Foot & Mortar Bags
Bricks per square foot, mortar bags and a buy quantity for any wall
Buying brick is unforgiving: a single course short and you're back at the yard mid-pour, while over-ordering ties up money in a pallet you'll never lay. This brick calculator turns a wall's length and height into an exact brick count, a mortar estimate, and a rounded-up number to actually order — so you buy once and lay it right.
The math starts with wall area. Wall area (sq ft) = length (ft) × height (ft). A wall 20 feet long and 8 feet high is 20 × 8 = 160 square feet. Multiply that area by the bricks needed per square foot, which depends on brick size and a standard 3/8-inch mortar joint:
• Modular brick (the most common US face brick, 7⅝ × 2¼ × 3⅝ in) ≈ 7 bricks per square foot of single-wythe wall. • Queen size ≈ 6.1 bricks per square foot. • King size ≈ 5.6 bricks per square foot.
So that 160 sq ft modular wall = 160 × 7 = 1,120 bricks before any waste. Real jobs always lose brick to cuts at corners and openings, chipping, and breakage on delivery, so masons add a waste factor — typically 10%. With 10% waste: 1,120 × 1.10 = 1,232, and because you can't buy a fraction of a brick you round up to 1,232 bricks.
Mortar is the second line item. A standard 70-lb bag of mortar mix lays roughly 30–40 modular bricks depending on joint thickness and how clean your work is. For 1,232 bricks at ~35 bricks per bag, that's about 36 bags — again rounded up so you don't run dry mid-wall.
This tool lets you pick the brick size, set your own waste percentage, and choose how many bricks one mortar bag covers, then reports: total wall area, bricks per square foot, raw brick count, bricks with waste, the rounded-up brick order, and mortar bags. Subtract the area of any windows or doors from your length × height first, and if you're laying a double-wythe (two-brick-thick) wall, double the result. Get the count right once and the wall takes care of itself.
📖 See also: How to Calculate a Tip (and Split the Bill)
Calculator
Fill in the fields and click "Calculate" for instant results.
📰 Formula
• Wall area (sq ft) = length (ft) × height (ft) • Bricks (raw) = area × bricks per sq ft • Bricks (to buy) = ceil(area × bricks per sq ft × (1 + waste%)) • Mortar bags = ceil(bricks to buy ÷ bricks per bag) Material constants (3/8 in mortar joint, single-wythe wall): • Modular brick ≈ 7 bricks per sq ft • Queen size ≈ 6.1 bricks per sq ft • King size ≈ 5.6 bricks per sq ft • Mortar: 1 bag (70 lb) ≈ 30–40 bricks (default 35) • Default waste factor ≈ 10%
📰 Formula
• Wall area (sq ft) = length (ft) × height (ft) • Bricks (raw) = area × bricks per sq ft • Bricks (to buy) = ceil(area × bricks per sq ft × (1 + waste%)) • Mortar bags = ceil(bricks to buy ÷ bricks per bag) Material constants (3/8 in mortar joint, single-wythe wall): • Modular brick ≈ 7 bricks per sq ft • Queen size ≈ 6.1 bricks per sq ft • King size ≈ 5.6 bricks per sq ft • Mortar: 1 bag (70 lb) ≈ 30–40 bricks (default 35) • Default waste factor ≈ 10%
🧪 Worked examples
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Example 2
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Example 3
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Example 4
⚠️ Common mistakes
- Forgetting the waste factor — corners, cuts and breakage easily eat 10%.
- Using modular's 7 bricks/sq ft for larger queen or king brick (which need fewer).
- Not subtracting window and door openings from the wall area before multiplying.
- Ignoring that a double-wythe (two-brick-thick) wall needs twice the brick.
- Rounding the brick or mortar quantity down instead of up — you can't buy half a unit.
💡 Tips
- Measure each wall, subtract openings, then add the areas before applying bricks per sq ft.
- Order 5–10% extra (waste) and keep leftovers — future bricks rarely match the dye lot.
- For a two-wythe structural wall, double the calculator's single-wythe brick count.
- Buy mortar by the 70-lb bag and round up; a bag costs less than a second trip to the yard.
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❓ Frequently asked questions
How many bricks do I need per square foot?
For standard modular brick with a 3/8-inch mortar joint, plan on about 7 bricks per square foot of single-wythe wall. Larger queen-size brick needs about 6.1 per square foot and king size about 5.6, because each brick covers more wall.
How do I calculate how many bricks I need for a wall?
Multiply the wall length by its height in feet to get the area, then multiply by the bricks per square foot for your brick size. A 20 ft by 8 ft modular wall is 160 sq ft × 7 = 1,120 bricks before waste.
How much waste should I add for brick?
A 10% waste factor is standard and covers cuts at corners and openings, chipping, and breakage during delivery and handling. For walls with lots of cuts or arches, bump it to 12–15%.
How many bricks does a bag of mortar lay?
A 70-lb bag of mortar mix lays roughly 30 to 40 modular bricks with a standard 3/8-inch joint. Thirty-five bricks per bag is a safe planning average; thicker joints or sloppier work use more.
How many bags of mortar do I need for 1,000 bricks?
At about 35 bricks per 70-lb bag, 1,000 bricks need roughly 29 bags. Always round up so you don't run out mid-wall, and add a bag or two for a margin on a hot, fast-drying day.
How do I account for windows and doors?
Calculate the area of each opening (width × height in feet) and subtract it from the wall's total area before multiplying by bricks per square foot. A 3 ft by 5 ft window removes 15 sq ft, or about 105 modular bricks.
What's the difference between modular, queen and king brick?
They're size standards. Modular brick is the classic US face brick at about 7 per square foot; queen size is a bit larger at 6.1, and king size larger still at 5.6. Bigger bricks mean fewer per square foot and faster coverage.
Does a double-wythe wall need twice the brick?
Yes. This calculator estimates a single-wythe (one-brick-thick) wall. A double-wythe or cavity wall has two leaves of brick, so double the brick count and the mortar accordingly.
How many bricks are in a standard pallet or cube?
A typical cube (pallet) of modular face brick holds about 500 bricks, though it varies by manufacturer from roughly 480 to 530. Divide your total brick count by the cube size to estimate how many pallets to order.