The calculator first computes wall face area (length × height). It then multiplies by the coverage rate for the selected brick or block type — which accounts for the mortar joint size — to get the base unit count. Your waste factor is added and the result is rounded up to a whole number.
Mortar bags are estimated based on how many units one 70 lb bag covers: approximately 30–35 standard bricks, or 8–10 CMU blocks. Cost is calculated separately for units and mortar, then totaled.
Coverage rates used: Standard modular brick = 6.75/sq ft; King brick = 4.5/sq ft; 8×8×16 CMU = 1.125/sq ft; 4×8×16 CMU = 2.25/sq ft.
Practical Tips for Brick & Block Work
Dry-stack first, then mortar. Lay out a full course of bricks or blocks without mortar to confirm your layout and spacing before committing. This is especially helpful around corners and openings.
Use a story pole. A marked vertical rod showing each course height keeps every course perfectly level without constant measuring. Essential for walls taller than 3 feet.
Butter both sides. Apply mortar to the bed (horizontal joint) and the head (vertical joint) of each unit for maximum bonding. Skipping the head joint weakens the wall significantly.
Keep mortar workable. Mortar that sits more than 60–90 minutes starts to stiffen and loses bonding strength. Mix only what you can use in that time, especially in hot or windy weather.
Cure slowly. Protect freshly laid brick work from direct sun, rain, and freezing temperatures for at least 48–72 hours. Cover with burlap or plastic sheeting if conditions are extreme.
Check plumb and level constantly. Use a spirit level after every 2–3 courses. Errors compound quickly — a wall that's 1/4 inch out of plumb at the bottom will be noticeably crooked by the time it's 4 feet tall.
Common Mistakes to Avoid
Wrong coverage rate. Many online guides use a generic "7 bricks per square foot" figure which is only accurate for one specific joint size and brick size. This calculator uses type-specific rates — choose the correct brick type to get an accurate count.
Not accounting for cuts. Openings (doors, windows) reduce the brick count, but cutting waste around them can easily use up 5–10% of your order. The 10% waste factor helps, but for walls with multiple openings, increase it to 15%.
Underestimating mortar. Many first-timers forget mortar entirely in the cost estimate, or assume one bag goes much further than it does. Mortar can add 10–20% to your total material cost.
Mixing too much mortar at once. If mortar stiffens before you use it, the temptation is to add water and re-temper it. This weakens the mix and is considered bad practice. Mix in small batches and discard anything that's been sitting for over 90 minutes.
Assumptions
◦Coverage rates: Standard brick 6.75/sq ft, King brick 4.5/sq ft, 8×8×16 CMU 1.125/sq ft, 4×8×16 CMU 2.25/sq ft. These assume a 3/8-inch mortar joint — slight adjustment for other joint sizes is built in.
◦Mortar yield: One 70 lb bag covers approximately 30–35 standard bricks or 8–10 CMU blocks with a 3/8-inch joint. Actual yield varies with joint size and application method.
◦Single wythe (one unit thick): This calculator assumes a single layer (wythe) of brick or block. For double-wythe or cavity walls, multiply the unit count by the number of wythes.
◦No openings deducted: The calculator does not subtract area for doors, windows, or other openings. Deduct opening area from wall area manually before calculating if needed.
◦Results are estimates: Actual material quantities vary with mason technique, joint consistency, and site conditions. Always verify with your supplier.
Frequently Asked Questions
Standard modular bricks (3.75×2.25×8 inches with 3/8-inch mortar joints) require approximately 6.75 bricks per square foot of single-wythe wall. King size bricks require about 4.5 per square foot. Use the calculator above for your specific brick type to get an accurate estimate.
A standard 8×8×16 CMU block with a 3/8-inch mortar joint covers about 0.89 square feet, so you need approximately 1.125 blocks per square foot. A 4×8×16 half block covers about 0.44 square feet — roughly 2.25 units per square foot. The calculator handles both types.
One 70 lb bag of Type S mortar covers approximately 30–35 standard modular bricks with a 3/8-inch joint. For CMU block, one bag covers 8–10 blocks. These are approximate figures — actual consumption varies with joint size, application method, and mason technique. Always add 10–15% extra.
Type S mortar (medium-high strength) is the most versatile and is suitable for most above-grade brick and block applications, retaining walls, and outdoor projects. Type N is softer and used for interior non-load-bearing walls. Type M is the hardest and used for foundations and below-grade work. Pre-mixed mortar bags from the hardware store are Type S unless labeled otherwise.
Materials only: standard brick walls cost roughly $5–$12 per square foot in materials (bricks + mortar). Installed cost with professional labor runs $15–$35 per square foot for simple walls, and $40–$70+ for decorative or structural work. CMU block is typically cheaper per square foot than brick but has a more industrial appearance.
For retaining walls, load-bearing walls, and any wall over 4 feet tall, vertical rebar (typically #4 or #5) placed in filled CMU cores is required by most building codes. Horizontal joint reinforcement (ladder wire) is also recommended every 2–3 courses. Always check your local code — unreinforced CMU walls are limited in height and load capacity.