Brick Calculator: Bricks and Mortar for a Wall

How do you calculate how many bricks you need?

Measure the wall face, subtract openings, and multiply by the number of bricks per square foot for your brick size. Then add a waste allowance. This is the wall area method that the Brick Industry Association (BIA) recommends in Technical Note 10.

Net area (ft²) = length × height − openings
Bricks = net area × bricks per ft² × (1 + waste %), rounded up
Mortar (ft³) = net area ÷ 100 × mortar per 100 ft²

Bricks per square foot is the face of one brick plus one mortar joint. A modular brick is 8 in long and 2 2/3 in high in nominal size, which already includes a 3/8 or 1/2 in joint, so it covers 8 × 2.667 = 21.33 in². 144 ÷ 21.33 = 6.75 bricks per ft², exactly BIA’s 675 per 100 ft².

The wall height should include any courses below grade. Every brick wall sits on a footing, and walls that retain soil or carry load need a design to your local code; size the concrete with the concrete footing calculator.

How many bricks per square foot? (by size)

It ranges from 3 to 6.75 bricks per ft² for the common sizes. The table is BIA Technical Note 10, Table 4 (running or stack bond, one wythe, no waste). Metric counts are BIA’s per-10 m² figures divided by 10.

Nominal vs specified. Modular brick are sold by nominal size: the specified (actual) brick plus the intended joint. A modular brick is specified 3 5/8 × 2 1/4 × 7 5/8 in for a 3/8 in joint, so three courses rise exactly 8 in. Queen and king brick are non-modular, so BIA lists their specified sizes; queen and king courses rise 16 in every five courses. Brick names vary by manufacturer, so check the plant’s size sheet.

How many bricks for common wall sizes?

The table gives bricks to buy with 10% extra for a single-wythe wall face with no openings. Multiply by two for a double-wythe wall.

For brick veneer on a house, measure each wall’s length × height, subtract windows and doors, and add the gable triangles (½ × base × height). A 1,500 ft² net veneer job in modular brick needs 10,125 bricks before waste and 10,632 with 5% extra.

How much mortar do I need for brick?

About 5.5 ft³ per 100 ft² of modular brick wall with 3/8 in joints, and 6.9 ft³ with 1/2 in joints. Smaller bricks mean more joints per square foot and so more mortar. These are BIA’s theoretical volumes for fully bedded units, before waste.

Turning volume into bags. Bagged mortar mix is the simplest route for small jobs: QUIKRETE’s Mortar Mix data sheet says one 80 lb bag lays up to 37 standard bricks, so 1,000 bricks need about 28 bags. On larger jobs masons mix masonry or portland cement with sand on site. BIA quotes the masons’ rule of thumb of eight bags of masonry cement per 1,000 modular brick, calling it “a very rough estimate” that includes an unspecified amount of waste. For the cement-to-sand proportions of Type N, S or M mortar, see ASTM C270 or the mortar calculator.

Mortar waste is real. Mortar dropped from the board, retempered past its working time or left in the mixer adds up. BIA says to adjust its numbers for waste; this calculator adds the same percentage to mortar as to bricks. Raise it for a first-time job.

Brick calculator in metric

The method is identical in metres: net wall area (m²) × bricks per m², then mortar from BIA’s per-10 m² column.

The 3/8 in joint in BIA’s tables is 9.5 mm; a 10 mm joint is close enough for estimating. Brick made to other national sizes are not in BIA’s table. For those, divide 1 m² by the face of one brick plus one joint: 1 ÷ ((length + joint) × (height + joint)), all in metres.

What changes the brick count?

Bond pattern, wall thickness and cutting. BIA’s numbers assume running or stack bond in a single wythe.

• Header courses. Patterns with full headers turn bricks sideways, so the face uses more brick. BIA Table 6 gives correction factors: common bond with headers every fifth course adds one fifth, so standard brick go from 655 to 786 per 100 ft², and mortar per 1,000 brick rises by 1/15, from 14.5 to 15.5 ft³.
• Double wythe. Two wythes double the brick. A mortared collar joint between them adds 3.13 ft³ of mortar per 100 ft² for a 3/8 in joint (BIA Table 5).
• Hollow brick. Laid in full mortar beds as veneer, BIA says hollow brick use about the same mortar as solid. With face-shell bedding, cut mortar by the void share, typically 25 to 35%.
• Openings and corners. Each opening means cut bricks at jambs and a lintel or arch above. Walls with many openings or short returns justify 10% extra, plain runs 5%.

Common brick estimating mistakes

• Using the brick’s actual size with no joint. A 7 5/8 × 2 1/4 in brick face without the joint gives 8.4 per ft² instead of 6.75, an overestimate of almost 25%.
• Mixing modular and non-modular counts. Queen and king are sized differently by each plant; read the size on the quote and pick the matching row.
• Forgetting below-grade courses and the gable ends of a house.
• Buying short. A second order may come from a different firing with a visible colour shift. Buy the whole job, plus extra, at once.
• Treating this as a design. Brick count says nothing about footings, ties, flashing, weep holes or reinforcement. Veneer and structural brick follow your local building code.

All results are ordering estimates from BIA’s published table. The brick plant’s size and count sheet take priority.