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Brick Calculator: How Many Bricks Do I Need?

This brick calculator estimates how many bricks and how much mortar a wall needs from its size, openings, brick size, and mortar joint, plus waste and an optional cost.

Units

Wall size in feet. Brick size and mortar joint in inches (3/8 in = 0.375).

Wall 1

Add another section for a second wall or a return.

Opening 1

Doors, windows, and other openings are subtracted from the wall.

Default 3/8 in. You can type 3/8 or 0.375.

Choosing a preset fills this in. Editing it switches the size to Custom.

5% is a typical allowance. Use 10% for many openings or corners.

Estimate only. About 7 bags (70-80 lb) per 1,000 modular bricks with 3/8 in joints. Check the bag label.

Brick estimate

Gross area
160 sq ft
Openings
12 sq ft
Net area
148 sq ft
Bricks per sq ft
6.857
Bricks before waste
1,014.857
Bricks with waste
1,066
Mortar bags
8

Bricks per sq ft = 144 / ((7.625 + 0.375) × (2.25 + 0.375)) = 144 / (8 × 2.625) = 6.857. Gross area = 160 sq ft. Openings = 12 sq ft. Net area = 160 − 12 = 148 sq ft. Bricks before waste = 148 × 144 / (8 × 2.625) = 1,014.857. With 5% waste, 1,014.857 × 1.05 = 1,065.6, which rounds up to 1,066 bricks. Mortar bags = 1,066 / 1,000 × 7 = 7.462, which rounds up to 8 bags.

Brick and bag counts round up. Mortar bags are an estimate to check against the bag label. The math stays in your browser.

How to use

  1. Choose imperial (feet and inches) or metric (meters and millimeters). Enter each wall's length and height, and add a section for another wall.
  2. Add each door, window, or other opening. The sample wall includes one 3 × 4 ft window. Remove a row when the wall has no opening.
  3. Pick a brick size or choose Custom, then set the mortar joint and the waste percent. Modular brick with a 3/8 in joint is the default.
  4. Optionally enter a price per brick and per mortar bag. Read the net area, brick count, mortar bags, and cost.

Formula

Bricks per square foot = 144 / ((brick length + joint) × (brick height + joint)), with length, height, and joint in inches. In metric, bricks per square meter = 1,000,000 / ((length + joint) × (height + joint)) with those sizes in millimeters. Net area is the wall area minus openings. Bricks before waste = net area × bricks per unit area. Bricks to order = that count × (1 + waste / 100), rounded up. Mortar bags = bricks to order / 1,000 × bags per 1,000, rounded up. That bag rate is an estimate to check against the bag label.

Example. A 20 × 8 ft wall is 160 sq ft. One 3 × 4 ft window removes 12 sq ft, leaving 148 sq ft. A modular brick (7-5/8 × 2-1/4 in) with a 3/8 in joint is 144 / (8 × 2.625) = 6.857 bricks per sq ft. That is 1,014.857 bricks before waste (about 1,015), and 1,066 bricks after 5% waste. At 7 bags per 1,000 bricks, the mortar estimate rounds up to 8 bags.

Example. The same wall at 10% waste needs 1,117 bricks.

Example. At $0.75 a brick and $8 a bag, 1,066 bricks and 8 bags cost $863.50.

Frequently asked questions

How many bricks per square foot?

About 6.9 standard modular bricks (7-5/8 x 2-1/4 in face) per square foot with 3/8 in mortar joints, often rounded to 7. Larger bricks such as queen or king sizes need fewer per square foot.

How is the brick count calculated?

Bricks per sq ft = 144 / ((brick length + joint) x (brick height + joint)) with all sizes in inches. Multiply that by the net wall area (wall area minus openings), then add waste.

Do I subtract windows and doors?

Yes. Subtract the area of each door, window, or other opening from the gross wall area before estimating. A 3 x 4 ft window removes 12 sq ft.

How much extra brick should I order?

Add about 5-10% for cuts, breakage, and color blending. Use the higher end for walls with many openings or corners.

How much mortar do I need for bricks?

A common rule of thumb is about 7 bags (70-80 lb) of mortar mix per 1,000 modular bricks with 3/8 in joints. Check the coverage printed on your mortar bag, since it varies by brand and joint size.

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