How Many Bricks per Square Foot? Modular Brick, Joints, Waste and Mortar

Modular brick laid with 3/8 in joints takes 6.75 bricks per sq ft of wall: 675 per 100 sq ft before waste, or 709 with a 5% allowance (BIA Technical Note 10). Standard-size brick takes 6.55 per sq ft.

A 20 ft × 8 ft wall with a 3 ft × 7 ft door is 139 sq ft net, so it takes 938.25 bricks net and 986 with 5% waste. Mortar for those is about 9.2 cubic feet, or 27 bags of 80 lb mix by the QUIKRETE label.

How do you calculate bricks per square foot?

bricks per sq ft = 144 ÷ ( module length × module height )
   module = brick size + mortar joint
modular (nominal 4 × 2-2/3 × 8 in brick, 3/8 in joints):
   module 8 in × 2-2/3 in = 21.33 sq in
   144 ÷ 21.33 = 6.75
bricks to buy = ceil( net wall area × bricks per sq ft × (1 + waste) )

1. Find the wall area in square feet (length × height) and subtract the openings. The square footage calculator handles gables and steps.
2. Multiply by 6.75 for modular brick with 3/8 in joints.
3. Add waste. BIA says “at least 5 percent” is added to net brick quantities as a general rule.
4. Round up to whole bricks.

The 144 is square inches per square foot. A modular brick plus its joints takes up an 8 in × 2-2/3 in space on the wall face, so three courses stack to 8 in of height and 144 ÷ 21.33 = 6.75. Standard-size brick takes 655 per 100 sq ft (6.55 per sq ft), per the BIA example.

Quick table: bricks by wall area

Modular brick, 3/8 in joints, laid in a running or stack bond with no headers. Openings are subtracted from the area first.

Worked example: a 20 × 8 ft wall with a door

• Gross area: 20 × 8 = 160 sq ft. Door: 3 × 7 = 21 sq ft. Net area: 160 − 21 = 139 sq ft.
• Bricks before waste: 139 × 6.75 = 938.25.
• With 5% waste: 938.25 × 1.05 = 985.16, so 986 bricks.
• Mortar, modular brick with 3/8 in joints at 5.5 cubic feet per 100 sq ft: 139 ÷ 100 × 5.5 = 7.645 cubic feet net. Adding 20% for mortar waste gives 9.17 cubic feet, about 1/3 cubic yard.
• Mortar by the QUIKRETE label of up to 37 standard bricks per 80 lb bag: 986 ÷ 37 = 26.65, so 27 bags.

The 20% mortar waste is a default inside BIA’s 15 to 25% range. Use the label rate for the mortar you buy: the 37-brick figure is QUIKRETE’s, for its Mortar Mix No. 1102.

How does the mortar joint change the count?

The joint is part of the module. A thinner joint puts bricks closer together and raises the count, and a thicker one lowers it. To see the size of the effect, the table moves the 8 × 2-2/3 in module by 1/8 in in each direction, which is what a joint 1/8 in thinner or thicker does to each side.

Only the middle row is a BIA figure. The other two are what-if arithmetic with the same formula, not a BIA table. In practice the joint and the course height are set by the design and the mason, so use the dimensions on your project.

How many square feet do 1,000 bricks cover?

1,000 ÷ 6.75 = 148.1 sq ft of modular brick wall before waste. With a 5% allowance, 1,000 ÷ (6.75 × 1.05) = 141.1 sq ft. That assumes a modular brick with 3/8 in joints, laid with the same face showing in every course.

How much mortar do bricks need?

BIA gives about 5.5 cubic feet of mortar per 100 sq ft of modular brick wall (8.1 cubic feet per 1,000 bricks) with 3/8 in joints. Standard-size brick uses 14.5 cubic feet per 1,000. BIA says to add 15 to 25% to the net mortar quantity for waste, and that 1 cubic foot of loose, damp sand yields about 1 cubic foot of mortar.

For bagged mix, use the label. One 80 lb bag of QUIKRETE Mortar Mix No. 1102 lays up to 37 standard bricks, so 100 bricks need 100 ÷ 37 = 2.7, or 3 bags, and 1,000 bricks need 1,000 ÷ 37 = 27.03, or 28 bags. A traditional rule of thumb quoted by BIA is eight bags of masonry cement per 1,000 modular bricks, a rough figure that includes waste and refers to a different product. The guide on how much mortar you need has bags per 100, 500 and 1,000 bricks.

Does the bond pattern change the number?

Yes. Patterns with header courses show the short end of the brick, which takes more bricks per square foot. BIA’s example for a common bond with a full header course every fifth course adds one fifth: 655 + 131 = 786 standard-size bricks per 100 sq ft. A plain running bond or stack bond has no extra factor. Ask your mason or the design for the bond before ordering.

Assumptions and limits

• Counts are for modular brick laid in walls with 3/8 in joints (an 8 × 2-2/3 in module) unless a row says otherwise. Queen, king, utility and other sizes have their own counts: use the manufacturer’s coverage figure or the BIA table.
• Paving bricks laid flat, corners, returns, arches and gable ends change the count. Waste depends on the cutting and the layout.
• Mortar type and strength, ties, flashing, lintels, reinforcement, wall height and lateral support are engineered items. Ask your building department or a licensed engineer. This guide counts bricks only.
• Mortar is cement-based. Wear gloves and eye protection.

Common questions