Brick Calculator

How to calculate how many bricks you need

Bricks are counted by the area of the wall. Work out the wall area in square feet, take away the area of the doors and windows, then multiply by the number of bricks that fit in one square foot. The Brick Industry Association calls this the wall-area method and says it is the most widely used way to estimate brickwork.

1. Wall area. Length × height, both in feet. A wall 20 ft long and 8 ft high is 160 square feet.
2. Subtract the openings. Each door or window is width × height. Take the total away from the wall area.
3. Bricks per square foot. 144 ÷ ((brick length + joint) × (brick height + joint)), with every measurement in inches. There are 144 square inches in a square foot.
4. Multiply and round up. Net area × bricks per square foot, then add your waste and round up to a whole brick.

Bricks per square foot by brick size

The sizes below come from Tables 1 and 2 of the Brick Industry Association’s Technical Note 10 (February 2009, checked October 2026). The counts use a 3/8 inch joint. The last column is the number the same document lists per 100 square feet.

Glen-Gery’s brick calculator lists 6.86 for modular, 6.55 for standard, 5.76 for queen, 4.80 for king, 4.57 for Norman, 4.50 for closure and 3.00 for utility, which are the same counts as the “Per sq ft” column. Brick names and exact sizes vary by manufacturer. The table notes that specified dimensions can vary within a range, so check the size printed on your brick and use “Custom size” if it differs.

Why the formula and the BIA count can differ

Modular brick is made so that three courses plus their joints measure 8 inches, which is 2 2/3 inches per course. At that spacing a modular brick works out to 144 ÷ (8 × 2 2/3) = 6.75 per square foot, the 675 per 100 square feet in the table. The formula uses the brick height plus a 3/8 inch joint, which is 2 5/8 inches per course, so it gives 6.86. The difference is the bed joint. The Technical Note says the real bed joint depends on the vertical coursing and the actual brick height, and that the mortar joints are specified so that the intended modular dimensions result. The formula count is the slightly higher one, which errs on the safe side for ordering. Norman shows the same gap for the same reason. For Queen and King the BIA counts are also lower, but they do not follow from the dimensions above, so ask your supplier. Use the figure that matches your brick.

Example: a 24 ft by 9 ft wall with a door and two windows

A garden wall is 24 ft long and 9 ft high. It has one door 3 ft by 6 ft 8 in and two windows 3 ft by 4 ft. You choose modular brick with a 3/8 inch joint and add 5% waste. These are the same figures you get from the calculator above.

Common wall sizes with modular brick

Wall height 8 ft unless noted, modular brick, 3/8 inch joint, no openings.

Waste, headers and corners

• Waste. The Brick Industry Association says to work out the net quantity first and then add an allowance, and that as a general rule at least 5 percent is added for breakage and waste. Some jobs need more. The waste box is empty by default, so the first number you see is the net count.
• Headers and other bonds. This calculator counts a single layer of bricks laid lengthwise, such as a running bond. Patterns with headers need more bricks. For example, the BIA gives a correction of one fifth more bricks for a common bond with a full header course every fifth course, which takes 655 standard bricks per 100 square feet to 786.
• Corners and cutting. The BIA suggests including partial bricks in the estimate to keep the bond at corners, and choosing a brick size that minimizes cutting where possible.

Mortar and how bricks are bought

The mortar line in the result uses one manufacturer’s figure. The QUIKRETE Mortar Mix data sheet (revised November 2020, checked October 2026) says an 80 lb bag lays up to 37 standard bricks. The sheet does not say what a standard brick is. Mortar use also depends on the brick size, the joint and the mason, so this is a starting point and not a guarantee. The BIA suggests adding 15 to 25 percent to the net mortar quantity for waste, and mentions a rough rule of thumb that eight bags of masonry cement lay 1,000 modular bricks. That is a different product from a pre-blended mix, so do not compare the two bag for bag.

Glen-Gery’s own calculator reports the price per thousand pieces, so ask your supplier whether a quote is per brick or per thousand. The “In thousands” line in the result gives your count that way. This calculator does not show prices, because they change with the brick, the color and the supplier. Get a quote for your count and ask whether delivery, a minimum order or a full pallet changes it.

Frequently asked questions