How to calculate bricks for a wall
The Brick Industry Association (BIA) calls the wall-area method the most widely used way to estimate brick, because it is simple and accurate. Work out the net wall area, the gross area minus doors and windows, and multiply it by the brick and mortar needed per square foot for your brick size. Then add waste. The square footage calculator helps with walls that are not rectangles.
Worked example: a wall 20 ft long and 8 ft high has 160 square feet. Take off a 3 by 7 ft door (21 square feet) and two 3 by 4 ft windows (24 square feet) and 115 square feet remain. Modular brick at 675 per 100 square feet makes 776.25 bricks, and with 5% waste you buy 816. The mortar is 115 × 5.5 ÷ 100 = 6.33 cubic feet, or 7.27 with 15% waste, and at Quikrete’s 37 bricks per 80 lb bag you need 25 bags of mortar mix.
Brick sizes and quantities per wall area
BIA Technical Note 10 lists the brick and mortar for each US size in its Table 4, for 3/8 inch joints and without waste. Modular brick are sized so that the brick plus its joint fits a 4 inch grid: a modular brick specified at 3 5/8 × 2 1/4 × 7 5/8 inches has a nominal size of 4 × 2 2/3 × 8 inches, and three courses rise 8 inches. Non-modular brick, like the standard and queen sizes, do not fit the grid. Brick names and sizes vary between manufacturers, so check the specified size of the brick you buy.
| Brick | Specified size (W × H × L) | Per 100 sq ft | Per m² | Mortar, cu ft per 100 sq ft |
|---|---|---|---|---|
| Modular | 3 5/8 × 2 1/4 × 7 5/8 in | 675 | 72.7 | 5.5 |
| Engineer modular | 3 5/8 × 2 13/16 × 7 5/8 in | 563 | 60.6 | 4.8 |
| Closure modular | 3 5/8 × 3 5/8 × 7 5/8 in | 450 | 48.4 | 4.1 |
| Roman | 3 5/8 × 1 5/8 × 11 5/8 in | 600 | 64.6 | 6.4 |
| Norman | 3 5/8 × 2 1/4 × 11 5/8 in | 450 | 48.4 | 5.1 |
| Engineer Norman | 3 5/8 × 2 13/16 × 11 5/8 in | 375 | 40.4 | 4.4 |
| Utility | 3 5/8 × 3 5/8 × 11 5/8 in | 300 | 32.3 | 3.7 |
| Meridian | 3 5/8 × 3 5/8 × 15 5/8 in | 225 | 24.2 | 3.5 |
| Queen | 2 3/4 to 3 × 2 3/4 × 7 5/8 to 8 in | 550 | 59.2 | 6.7 |
| King | 2 3/4 to 3 × 2 5/8 to 2 3/4 × 9 5/8 to 9 3/4 in | 455 | 49 | 6.5 |
| Standard | 3 5/8 × 2 1/4 × 8 in | 655 | 70.5 | 9.5 |
| Engineer standard | 3 5/8 × 2 13/16 × 8 in | 539 | 58 | 8.2 |
| Closure standard | 3 5/8 × 3 5/8 × 8 in | 430 | 46.3 | 7 |
The per square meter column converts BIA’s per 100 square feet figure. For walls two brick deep with a solidly mortared joint between them, the calculator doubles the brick and mortar and adds the collar joint. BIA Table 5 gives 3.13 cubic feet of mortar per 100 square feet for a 3/8 inch collar joint, which is the joint thickness times the wall area. Quikrete’s yield of 37 bricks per bag covers the joints around each brick, so for a wall two deep the calculator raises the bag count by the share of mortar the collar joint adds.
UK brick size
The Brick Development Association’s guide to designing to brickwork dimensions names 215 × 102.5 × 65 mm as the most widely used work size for UK clay bricks and bases its tables on a nominal 10 mm mortar joint. That gives a co-ordinating size of 225 × 112.5 × 75 mm. Manufacturers list the same work size in their data sheets, for example Forterra for bricks made to BS EN 771-1.
One brick with its joints covers 0.225 × 0.075 = 0.016875 m² of wall face, so a single skin needs 59.3 bricks per square meter. A garden wall 5 m long and 1.8 m high, 9 m², takes 533 bricks, or 560 with 5% waste. For UK and custom sizes the calculator works out the mortar from the dimensions: the wall volume minus the brick volume, about 17.61 liters per square meter of single skin. That assumes solid bricks and full joints. Checked against BIA’s modular brick (7 5/8 inches long, 3/8 inch joints, three courses to 8 inches), the same method gives 675 bricks and 5.46 cubic feet of mortar per 100 square feet, against BIA’s 675 and 5.5.
Mortar, sand and waste
Quikrete’s data sheet for its Mortar Mix says each 80 lb bag lays up to 37 standard bricks, so the calculator shows the bag count for modular and standard brick, the sizes closest to a standard brick. For other sizes it shows the mortar volume from BIA Table 4. BIA recommends adding 15 to 25 percent to the net mortar for waste and at least 5 percent to the brick. For 100 square feet of modular brick that is 675 bricks and, with 15% mortar waste, 21 bags.
BIA also quotes masons’ rule of thumb that eight bags of masonry cement lay 1,000 modular brick, which it calls a very rough estimate that includes an unspecified amount of waste. If you mix your own mortar, 1 cubic foot of loose, damp sand yields about 1 cubic foot of mortar. Patterns with header courses, like common bond, need more brick and mortar than the running bond the tables assume. For a slab or footing under the wall, use the concrete calculator.
How to use the brick calculator
- 1Choose feet or meters and enter the length and height of the wall.
- 2Enter the number and size of doors and windows. Set the count to 0 if there are none.
- 3Pick your brick size, or enter a custom size with its joint, and choose a wall one or two bricks deep.
- 4Choose the brick and mortar waste, then read the bricks to buy, the mortar volume and the bags of mortar mix.
Sources
- Brick Industry Association: Technical Note 10, Dimensioning and Estimating Brick Masonry (Tables 1, 2, 4 and 5, waste)
- Brick Development Association: Designing to Brickwork Dimensions, Technical Guide 4 (2023)
- Forterra: brick technical data sheet (standard work size 215 × 102.5 × 65 mm, BS EN 771-1)
- Quikrete: Mortar Mix data sheet (up to 37 standard bricks per 80 lb bag)
Frequently asked questions
How many bricks are in a square foot?
For US modular brick with 3/8 inch joints, the Brick Industry Association counts 675 brick per 100 square feet, so 6.75 per square foot. Standard non-modular brick (3 5/8 × 2 1/4 × 8 in) comes to 655 per 100 square feet, Norman brick to 450.
How many bricks are in a square meter?
With the standard UK brick of 215 × 102.5 × 65 mm and 10 mm joints, each brick takes up 225 × 75 mm of wall face, so 1 ÷ (0.225 × 0.075) = 59.3 bricks per square meter for a single skin (half-brick) wall. A wall two bricks thick needs twice as many. US modular brick comes to about 72.7 per square meter.
How many bags of mortar do I need for 1,000 bricks?
Quikrete states that one 80 lb bag of its Mortar Mix lays up to 37 standard bricks, so 1,000 bricks take at least 28 bags (1,000 ÷ 37 = 27.03, rounded up). The Brick Industry Association recommends adding 15 to 25 percent to the mortar for waste, which makes about 32 to 34 bags.
How much extra brick should I order?
The Brick Industry Association adds at least 5 percent to the net brick count for breakage and waste, and more where the job calls for it. Walls with many corners, openings or cuts usually need more than a plain wall.
Do I subtract windows and doors?
Yes. The wall-area method multiplies the net wall area, the gross area minus the openings, by the brick per square foot. Enter your doors and windows and the calculator subtracts them before counting.
How much sand do I need for mortar?
If you mix mortar from cement and sand yourself, the Brick Industry Association gives the rule of thumb that 1 cubic foot of loose, damp sand yields about 1 cubic foot of mortar. So plan about as much sand as mortar volume. Premixed bags like mortar mix already contain the sand.