Brick Calculator: How Many Bricks Do I Need?

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A wall one brick thick of standard modular brick takes about 6.75 bricks per square foot, or 675 per 100 sq ft, according to the Brick Industry Association (BIA). To estimate, multiply the wall area, minus doors and windows, by 6.75 and add at least 5 percent for breakage and cuts. A wall 20 ft long and 8 ft high (160 sq ft) needs 1,080 modular bricks, or 1,134 with 5 percent extra.

Our brick calculator also counts bags of mortar mix and the mortar in the joints for seven brick sizes. Set the bricks-per-bag field to match your mortar bag.

How many bricks do you need?

Enter the wall size, the area of any doors and windows, and your brick size. Results include bricks and bags of mortar mix.

ft
ft
sq ft
bricks
%

Counts are for a wall one brick thick in running bond, from the Brick Industry Association (Technical Note 10). QUIKRETE rates an 80 lb bag of Mortar Mix at up to 37 standard bricks; check your bag.

How to measure a brick wall

  1. Measure the length in feet along the base of the wall. For a wall with corners, add up the runs but count each corner only once. Divide inches by 12 to get feet (20 ft 6 in is 20.5 ft).
  2. Measure the height in feet from where the brick starts, such as the top of the footing, to where it stops, such as the wall cap or soffit. For a triangular gable, enter its width as the length and half its peak height as the height, then add that count to the main wall.
  3. Add up the openings. Multiply the width by the height of each door, window, and vent, and enter the total in "Doors and windows to subtract." A 3 × 7 ft door is 21 sq ft. BIA's wall-area method works from the net wall area: the gross area less the openings.
  4. Confirm the brick size. Check the specified size on the product sheet or measure a brick, and pick the option whose face (length × height) matches. Depth doesn't change the count for a wall one brick thick.
  5. Pick the mortar joint. The default is 3/8 in: a modular brick's 7 5/8 in length plus a 3/8 in joint makes its 8 in nominal length. Choose 1/2 in if your plans or existing brickwork call for it.
  6. Enter your bag yield and extra. Use the "bricks per bag" figure on your mortar bag, and keep the extra at 5 percent or more. BIA notes that job conditions may warrant a higher percentage.

The brick formula

The calculator follows BIA's wall-area method, which multiplies the net wall area by a known quantity of material per square foot:

  • Net wall area (sq ft) = length (ft) × height (ft) − doors and windows (sq ft)
  • Bricks per sq ft = BIA bricks per 100 sq ft ÷ 100
  • Bricks = net wall area × bricks per sq ft × (1 + extra % ÷ 100), rounded up
  • Mortar bags = bricks ÷ bricks per bag, rounded up
  • Mortar in the joints (cu ft) = net wall area ÷ 100 × BIA mortar per 100 sq ft for your joint

Why 6.75? BIA defines a brick's nominal size as its specified (manufactured) size plus the intended mortar joint. A modular brick is specified at 3 5/8 × 2 1/4 × 7 5/8 in, its nominal size is 4 × 2 2/3 × 8 in, and three courses (three bricks and three joints) rise 8 in. One brick and its joints cover 8 × 2 2/3 = 21.33 sq in, and 144 ÷ 21.33 = 6.75 bricks per square foot.

Worked example (the calculator's default values)

A wall 20 ft long and 8 ft high with no openings, modular brick, 3/8 in joints, 37 bricks per bag of mortar mix, and 5 percent extra:

  1. Net wall area: 20 × 8 − 0 = 160 sq ft
  2. Bricks per sq ft: 675 ÷ 100 = 6.75
  3. Bricks before extra: 160 × 6.75 = 1,080
  4. With 5 percent extra: 1,080 × 1.05 = 1,134 bricks
  5. Mortar bags: 1,134 ÷ 37 = 30.6, rounded up to 31 bags
  6. Mortar in the joints: 160 ÷ 100 × 5.5 = 8.8 cu ft

The calculator shows: "You need 1,134 bricks. 160 sq ft of wall at 6.75 modular bricks per sq ft, plus 5% extra. About 31 bags of mortar mix at 37 bricks per bag; the joints hold about 8.8 cu ft of mortar before waste."

Check it by courses: an 8 ft (96 in) wall at three courses per 8 in is 36 courses, and a 20 ft (240 in) run is 30 bricks per course. 36 × 30 = 1,080 bricks before extra, the same answer.

Now add a 3 × 7 ft door (21 sq ft). The net area drops to 139 sq ft, and 139 × 6.75 × 1.05 = 985.2, rounded up to 986 bricks and 27 bags (986 ÷ 37 = 26.6). One door saves 148 bricks.

Brick and mortar: bags vs. volume

The bag count comes from the maker's yield. QUIKRETE says each 80 lb bag of its Mortar Mix, a Type N mortar, will lay up to 37 standard bricks. "Up to" is a best case, so don't cut your order close.

The volume comes from BIA Table 4 and is theoretical: the mortar that ends up in the joints. BIA says to add 15 to 25 percent to net mortar quantities, so the example's 8.8 cu ft becomes about 10.1 to 11.0 cu ft. A 1/2 in joint raises the volume to 11.0 cu ft before waste, but the wall still takes 1,134 bricks, because BIA lists one brick count per size.

Mixing your own changes the bag count. QUIKRETE Masonry Cement comes in 70 lb bags blended with sand: one bag plus 240 lb of mason's sand lays about 144 standard bricks. Enter 144 and the example wall needs 8 bags (1,134 ÷ 144 = 7.9), plus sand. BIA reports a masons' rule of thumb of eight bags of masonry cement per 1,000 modular brick, which it calls "a very rough estimate."

How many bricks for a 20 by 8 foot wallFront view of a brick wall 20 feet long and 8 feet high, 160 square feet, laid in running bond: 30 modular bricks per course and 36 courses, 1,080 bricks. A close-up of one square foot shows one and a half bricks across and four and a half courses: each brick with its joints covers 8 by 2 and two thirds inches, 21.33 square inches, so 144 divided by 21.33 is 6.75 bricks per square foot. 160 times 6.75 is 1,080 bricks, plus 5 percent extra is 1,134 bricks, and at 37 bricks per 80 pound bag of mortar mix that is 30.6, so 31 bags.COUNT BRICKS FROM THE WALL AREALength 20 ftHeight8 ftOne square foot of modular brickNominal face with joints: 8 × 2⅔ in144 sq in ÷ 21.33 sq in = 6.75 bricks1½ bricks across × 4½ courses160 sq ft20 ft × 8 ft wall1,080 bricks160 × 6.75 per sq ft1,134 bricks1,080 + 5% extraCheck: 36 courses × 30 bricks = 1,080, + 5% extra = 1,134 bricksMortar mix: 1,134 ÷ 37 bricks per bag = 30.6 → 31 bags
Multiply the wall area by the bricks per square foot, then add the extra: 20 × 8 ft = 160 sq ft × 6.75 = 1,080 modular bricks, plus 5% = 1,134, and 1,134 ÷ 37 bricks per bag = 30.6, so 31 bags of mortar mix.

Bricks per square foot by brick size

The seven sizes in the calculator, from BIA Technical Note 10, Table 4 (running bond, no waste added):

BrickFace (length × height)Bricks per sq ftBricks per 100 sq ftMortar per 100 sq ft, 3/8 in jointMortar per 100 sq ft, 1/2 in joint
Modular7 5/8 × 2 1/4 in6.756755.5 cu ft6.9 cu ft
Standard8 × 2 1/4 in6.556559.5 cu ft11.0 cu ft
Queen7 5/8 × 2 3/4 in5.55506.7 cu ft7.4 cu ft
King9 5/8 × 2 5/8 in4.554556.5 cu ft7.3 cu ft
Engineer modular7 5/8 × 2 13/16 in5.635634.8 cu ft6.1 cu ft
Norman11 5/8 × 2 1/4 in4.54505.1 cu ft6.5 cu ft
Utility11 5/8 × 3 5/8 in33003.7 cu ft4.7 cu ft

BIA notes that a brick's name and size can vary by region and by manufacturer, and it gives ranges for some sizes: queen brick can be 7 5/8 or 8 in long, and king brick 9 5/8 to 9 3/4 in long. If your brick doesn't match a row, ask the supplier how many it takes per square foot.

How many bricks in a wall: common sizes

Modular brick, 3/8 in joints, 5 percent extra, and 37 bricks per bag, straight from the calculator:

Wall (length × height)Wall areaBricks with 5% extraBags of mortar mix
10 × 3 ft30 sq ft2136
10 × 4 ft40 sq ft2848
20 × 4 ft80 sq ft56716
20 × 8 ft160 sq ft1,13431
30 × 8 ft240 sq ft1,70146
40 × 8 ft320 sq ft2,26862

Tips and common mistakes

  • Skipping the openings, or subtracting them twice. Enter the total area of doors and windows once. Leaving out a garage door or large windows can add hundreds of bricks.
  • Cutting the extra too thin. BIA's general rule is at least 5 percent over the net brick quantity. Raise it for walls with many corners, openings, or cut brick.
  • Assuming every brick is the same size. Check the specified size, the brick itself without the joint, before you pick an option. The example wall in queen brick takes 924 bricks, not 1,134.
  • Ignoring the joint size. A 1/2 in joint needs more mortar than 3/8 in: 6.9 vs. 5.5 cu ft per 100 sq ft for modular brick. Match your plans or the brickwork you're adding to.
  • Buying brick in batches. BIA's brick selection note says it is best to purchase all brick from the same production run, because there are typically slight color variations between runs. Order the full quantity, extra included, at once.
  • Laying one cube at a time. Color can occasionally vary within a run too, so BIA recommends mixing straps of brick from different cubes around the wall as you lay.

Estimates only: when to call a pro

This calculator estimates material for non-structural work such as brick veneer, garden walls, and planters. The count doesn't include the footing or foundation. Load-bearing walls, retaining walls, chimneys, and fireplaces need a qualified professional and your local building code. For example, under the 2015 IRC (section R404.4), a retaining wall not supported at the top that holds back more than 48 in of unbalanced fill must be designed using accepted engineering practice, and so must one over 24 in high that resists loads beyond the soil.

Frequently asked questions

How many bricks per square foot?

About 6.75 for modular brick, or 675 per 100 sq ft, from BIA's Table 4. Standard brick takes 6.55, queen 5.5, king 4.55, and Norman 4.5 per square foot. Add at least 5 percent for breakage and cuts.

How many bricks are in a wall 20 ft long and 8 ft high?

A 160 sq ft wall of modular brick takes 1,080 bricks, or 1,134 with 5 percent extra: 36 courses of 30 bricks each. A 3 × 7 ft door brings it down to 986 bricks.

How many bags of mortar do I need for 1,000 bricks?

At up to 37 standard bricks per 80 lb bag of QUIKRETE Mortar Mix, about 28 bags. QUIKRETE Masonry Cement, at about 144 standard bricks per 70 lb bag mixed with 240 lb of sand, needs about 7 bags. Always check your bag.

What size is a modular brick?

Its specified size is 3 5/8 × 2 1/4 × 7 5/8 in. With a 3/8 in mortar joint, its nominal size is 4 × 2 2/3 × 8 in, so three courses rise 8 in.

How much extra brick should I order?

BIA's general rule is at least 5 percent over the net count, and 15 to 25 percent over the theoretical mortar volume. Order all the brick at once so it comes from the same production run.

Can I use the calculator for a wall two bricks thick?

Run it once for each layer (wythe) and add the counts. If the joint between the layers is filled solid, BIA estimates that mortar separately, so it's extra. A wall that carries load needs a pro's design.

How much mortar do I need per 100 square feet of brick?

BIA's Table 4 puts the mortar in the joints of a modular brick wall at 5.5 cu ft per 100 sq ft with 3/8 in joints and 6.9 cu ft with 1/2 in joints. Those volumes are theoretical, so BIA says to add 15 to 25 percent for waste.

Why should I order all my brick at once?

BIA's brick selection note says it is best to purchase all brick from the same production run, because there are typically slight color variations between runs. Color can occasionally vary within a run too, so BIA recommends mixing straps of brick from different cubes as you lay.