Brick Calculator

The Mortar Joint Is Part of the Brick's Footprint

A standard modular brick measures 8 in by 2.67 in, but it never sits alone in a wall — a mortar joint runs along every edge, and that joint, typically 0.375 in, effectively enlarges each brick's footprint in the finished wall. Counting bricks without accounting for the joint consistently overstates how many actually fit.

The Formula

Wall Area = (Wall Length × Wall Height) − Opening Area
Brick Footprint = ((Brick Length + Joint) × (Brick Height + Joint)) ÷ 144
Bricks Needed = Wall Area ÷ Brick Footprint

The calculator subtracts any door and window opening area from the gross wall area, then works out the effective footprint of one brick plus its mortar joint on two sides, converted to square feet. Dividing wall area by that footprint gives the raw brick count, which is then increased by a waste allowance — 10% by default — for cuts, corners, and breakage, and rounded up.

Where This Calculation Matters

Veneer walls and facades — brick veneer over framing is priced and ordered by the piece, so an accurate count avoids both a costly reorder and excess inventory sitting on a pallet.
Garden walls and patios — the same footprint math applies whether the bricks are laid vertically in a wall or flat in a paving pattern, just with a different opening area (zero, typically).
Non-standard brick sizes — the calculator accepts custom brick length, height, and joint width, so it applies equally to Roman, Norman, or reclaimed brick with different nominal dimensions.

Standard Modular Brick: Wall Size vs. Brick Count

Bricks needed using standard modular brick (8 in × 2.67 in, 0.375 in joint), including 10% waste
Wall Size	Wall Area	Bricks Needed
10 ft × 8 ft	80 sq ft	497
20 ft × 8 ft	160 sq ft	994
30 ft × 10 ft	300 sq ft	1,864

These figures work out to roughly 6.2 bricks per square foot of wall, which is a useful rule of thumb for standard modular brick with a standard joint.

How to Use This Calculator

Enter the Wall Length and Wall Height in feet.
Optionally enter the Brick Length and Brick Height in inches — defaults to 8 in and 2.67 in for standard modular brick.
Optionally enter the Mortar Joint thickness in inches — defaults to 0.375 in.
Optionally enter the Doors/Windows Opening Area in square feet to subtract from the total.
Optionally adjust the Waste % — defaults to 10%.
Select Calculate to see the total number of bricks needed.

Related Calculations

Building a block wall instead? The Concrete Blocks Calculator uses the same footprint approach for CMU block, and the Cement Bags Calculator can help size the mortar mix that goes between the bricks.