How Do I Calculate How Many Bricks I Need?
Multiply your wall area (square feet) by bricks per square foot, then add 10–15% for waste. Standard bricks at a 3/8″ joint run about 6.75 per square foot. A 20×8-foot wall needs roughly 1,090 standard bricks with 10% waste.
Estimating bricks for a wall comes down to one key calculation: how many bricks fit in a single square foot of wall face. Once you have that number, multiply by your total wall area and add a waste factor for cuts, breakage, and irregularities.
Formula:Bricks per square foot = 144 sq inches ÷ (brick length + joint width) × (brick height + joint width). For a standard brick at a ⅜” joint, this works out to roughly 6.75 bricks per square foot. Total bricks = wall area (sq ft) × bricks per sq ft × (1 + waste factor).
For a 20 ft × 8 ft wall using standard bricks at a ⅜” joint with 10% waste, that comes to approximately 1,090 bricks. Always round up to the nearest full brick when ordering — suppliers sell by the unit, not by fractions.
What Are the Standard Brick Sizes?
Standard modular brick (7-5/8″ × 2-1/4″) is the most common, running about 6.75 bricks per square foot. Queen bricks yield 5.76 per square foot, king bricks 5.44, and utility bricks 3.00. Choosing a larger brick reduces labor and unit count but changes the wall's visual proportions.
The four most widely used brick sizes in North America each have different face dimensions, which directly affects the brick count for any given wall area.
- Standard / Modular (7⅝” × 2¼”): The most common brick in residential and commercial construction. Also called a modular brick, it courses out at 4 bricks per foot of height when laid with a ⅜” joint. About 6.75 bricks per square foot of wall.
- Queen (7⅝” × 2¾”): Same length as standard but taller in height. Queen bricks are popular when builders want fewer courses per wall — they course out at 3.43 bricks per foot of height. About 5.76 bricks per square foot.
- King (9⅝” × 2⅝”): Longer than standard, king bricks lay faster and are often used in veneer applications where the slightly wider module suits the design. About 5.44 bricks per square foot at standard joints.
- Utility (11⅝” × 3⅝”): The largest of the four. Utility bricks dramatically reduce labor because fewer units are needed per wall. Common in commercial block walls and industrial buildings. About 3.00 bricks per square foot.
How Does Mortar Joint Width Affect Brick Count?
Standard masonry uses a 3/8″ joint. Wider joints (1/2″) slightly increase brick count per square foot and consume significantly more mortar per course. Thin joints (1/4″) are common in restoration work and require stiffer mortar.
The width of your mortar joint affects brick count in two ways: it changes the effective face size of each unit (and therefore the count per square foot), and it changes how much mortar you need overall. Standard masonry practice uses a ⅜” joint, which offers the right balance of strength, appearance, and workability.
A ¼” (thin) joint is common in restoration work or when matching historic brick courses. It requires a stiffer mortar mix and more precise laying technique. A ½” (wide) joint is used with rougher brick textures or when the design calls for pronounced horizontal lines — it slightly increases brick count per square foot because the joint takes up more of each course height.
In practice, the difference between a ¼” and ½” joint is small for brick count but meaningful for mortar: wider joints consume significantly more mortar per course.
How Many Bags of Mortar Do I Need?
Plan on 7 bags of 80-pound mortar per 1,000 standard bricks at a 3/8″ joint. A 1/2″ joint needs about 33% more mortar. Pre-mixed bags work for small jobs; site-mixed mortar is more economical for larger projects.
The industry rule of thumb is approximately 7 bags of 80 lb mortar per 1,000 standard bricks when using a ⅜” joint. This figure accounts for typical bed joints and head joints in a running bond pattern. Adjust proportionally for other joint widths: a ½” joint requires roughly 33% more mortar than a ⅜” joint, while a ¼” joint requires about 33% less.
Pre-mixed mortar bags are convenient for smaller jobs. For larger projects, site-mixed mortar (Portland cement, hydrated lime, and masonry sand) is more economical. A standard type S or type N mortar mix is appropriate for most exterior brick walls. Type S is stronger and preferred for below-grade applications and areas subject to frost.
How Do I Account for Doors and Windows?
Calculate total wall area first, then subtract each door and window opening. Apply your waste factor to the net masonry area. Use 12–15% waste for walls with multiple openings due to extra cuts around jambs and sills.
When your wall has door or window openings, calculate the total wall area first, then subtract each opening. For example, a 20 ft × 8 ft wall (160 sq ft) with one standard door opening (3 ft × 6.8 ft = 20.4 sq ft) and one window (3 ft × 4 ft = 12 sq ft) has a net masonry area of 160 − 20.4 − 12 = 127.6 sq ft.
Apply your waste factor to the net area, not the gross. This is where the 10% waste factor earns its keep — brick cuts around window jambs, sills, and door frames generate more waste than straight running bond, so some masons increase the waste allowance to 12-15% for walls with multiple openings.
Also account for any soldier or rowlock courses above openings (bricks laid on end or on edge for lintels and sills), as these consume extra material and require different counting.
How Should I Order Bricks?
Always order from a single production run to avoid color variation between kiln batches. Order 5–10% extra and store spares for future repairs. Request bricks from the same lot number if your project spans multiple deliveries.
Related Calculators
- Rebar Calculator— Size vertical reinforcement for block and brick walls
- Sand Calculator— Estimate mortar sand by the ton
Written by Daniel McCarney — AceCalc