Brick Calculator: How Many Bricks Do I Need?

How many bricks per square foot?

Multiply the net wall area (the walls minus doors and windows) by the bricks per square foot for your size, then add waste. The Brick Industry Association's Technical Note 10 lists 675 modular bricks per 100 sq ft of single-wythe wall, 563 engineer modular, 550 queen, 455 king, 450 Norman and 300 utility, none of it counting waste.

Worked example: a 30 × 8 ft wall with two 15 sq ft windows is 210 sq ft. In modular brick that is 1,417.5 bricks; with 5 % for breakage, order 1,489. A double wall needs twice as many.

Mortar: volume and bags

BIA Table 4 gives the mortar in the joints: 8.1 cubic feet per 1,000 modular bricks with ⅜ in joints and 10.3 with ½ in joints, and it says to add 15 to 25 % for waste. The example wall needs 11.5 cu ft, or 13.2 with 15 % extra.

For bagged mix, Quikrete says an 80 lb bag of its Mortar Mix lays up to 37 standard bricks or 13 8 × 8 × 16 in blocks. The calculator divides the bricks (with the mortar allowance) by that figure: 45 bags for the example. BIA quotes the masons' rule of thumb of eight bags of masonry cement per 1,000 modular bricks and calls it very rough.

Brick sizes: nominal and specified

A modular brick is specified at 3⅝ × 2¼ × 7⅝ in so that with a ⅜ in joint it fills a nominal 4 × 2⅔ × 8 in: three courses make 8 in. With ½ in joints the specified size drops to 3½ × 2¼ × 7½ in. Queen and king brick are non-modular; their sizes change with the joint the maker intends.

Names and sizes vary between manufacturers, so check the size on the pallet or the data sheet. For a size not in the list, choose Custom and type the actual length, height and depth.

Concrete block

A standard 8 × 8 × 16 in block is made 7⅝ × 7⅝ × 15⅝ in so that with ⅜ in joints its face covers 8 × 16 in, which the Concrete Masonry and Hardscapes Association puts at 8/9 sq ft. That is 112.5 blocks per 100 sq ft, or 119 with the 5 % waste its estimating guide adds.

Tips for the site visit

Measure each wall, count the openings, check the footing and note anything that changes the count: header courses in common, English or Flemish bond, soldier courses, piers and returns. Codes vary by place, and the engineer's drawings, the brick maker's instructions and the local code win over any calculator.

Then write down what the customer told you: the brick and mortar colour, the bond, the joint finish, access for the mixer and the pallets, and the date it must be done. Those notes decide the quote as much as the brick count does.

Sources, checked October 2026. All figures are estimates:

• Brick Industry Association: Technical Note 10, Dimensioning and Estimating Brick Masonry (sizes, Table 4, waste)
• Quikrete Mortar Mix data sheet: an 80 lb bag lays up to 37 bricks or 13 blocks
• CMHA TEK 04-02A: estimating concrete masonry (8/9 sq ft per 8 × 16 in unit)

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