Brick Calculator
Count bricks before you order the cube. Enter wall length and height in feet, subtract door and window openings in square feet, pick a brick size (modular, queen, king, or utility), and get bricks with waste plus 80 lb mortar bag count.
Example: with Wall length (ft) 20 · Wall height (ft) 8 · Openings — doors/windows (sq ft) 21 · Brick size Modular 7-5/8 × 2-1/4 in (6.75 per sq ft) · Waste factor (%) 10 → Bricks to order: 1,033 bricks.
- Net wall area139 sq ft
- Mortar (premixed)28 × 80 lb bags
Computed by the calculator below using its default values. Change any input to see your own numbers.
Modular brick lays up at 6.75 per square foot with 3/8-inch joints. An 80 lb bag of mortar mix lays roughly 37 bricks.
Bricks per square foot is the whole game
Brick estimating reduces to one number: how many units fill a square foot of wall face, mortar joints included. A modular brick presents a 7-5/8 × 2-1/4 inch face; add the standard 3/8-inch joint and it occupies a nominal 8 × 2-2/3 inches, which packs 6.75 bricks into every square foot of running bond. Bigger faces mean fewer bricks: queen-size units run about 5.76 per square foot, kings 4.8, and big utility brick just 3. Multiply net wall area (gross minus doors and windows) by the rate, add waste, and round up.
A 20 × 8 foot wall with one 21-square-foot door is 139 net square feet — about 938 modular bricks, call it 1,035 with 10% waste.
Waste, mortar, and what this covers
Ten percent waste is the standard allowance for cut brick at corners and openings, breakage in handling, and culls with chipped faces; tight patterns like herringbone or lots of openings push it to 15%. For mortar, preblended 80 lb bags lay roughly 37 modular bricks each per manufacturer coverage charts, so a 1,000-brick job needs about 27 bags — masons mixing cement, lime, and sand on site figure it differently. These counts are for a single-wythe veneer face; a double-wythe structural wall doubles the brick and adds header courses.
How it’s calculated
Net area = length × height − openings. Bricks = net area × units-per-sq-ft × (1 + waste%), rounded up. Unit rates (6.75 modular, 5.76 queen, 4.8 king, 3.0 utility) assume running bond with 3/8-inch mortar joints, per Brick Industry Association sizing. Mortar bags = bricks ÷ 37 per 80 lb preblended bag (manufacturer coverage), rounded up.
Single-wythe running bond only — double-wythe walls, stack bond with cut patterns, and corbels change both brick and mortar counts.
Brick sizes and coverage
| Type | Face size (specified) | Bricks per sq ft |
|---|---|---|
| Modular | 7-5/8 × 2-1/4 in | 6.75 |
| Queen / oversize | ≈ 7-5/8 × 2-3/4 in | 5.76 |
| King | ≈ 9-5/8 × 2-5/8 in | 4.8 |
| Utility | 11-5/8 × 3-5/8 in | 3.0 |
Brick Industry Association size conventions with 3/8 in joints, running bond; queen and king dimensions vary slightly by region.
Common mistakes
- Forgetting to subtract doors and windows — one entry door is about 21 sq ft, or 140+ modular bricks.
- Estimating from the brick's specified size without the mortar joint, which overcounts by around 15%.
- Ordering for one wythe when the design is a double-wythe structural wall.
- Skipping waste: corners and openings generate cut brick, and every cube includes a few culls.
Frequently asked questions
What is the brick calculation formula?
Bricks = (wall length × height − openings) × bricks per sq ft × (1 + waste). For modular brick that rate is 6.75 per square foot of running bond with 3/8-inch joints.
How many bricks per square foot?
6.75 for standard modular brick, about 5.76 for queen, 4.8 for king, and 3.0 for utility sizes — all counted with 3/8-inch mortar joints. Rounding to 7 per square foot builds in a small cushion for modular.
How much mortar do I need per 1,000 bricks?
About 27 bags of 80 lb preblended mortar mix at the common coverage of 37 bricks per bag. Site-mixed mortar is usually figured instead as roughly 7 bags of masonry cement plus a cubic yard of sand per 1,000 modular bricks.
Do these counts include the mortar joints?
Yes — the per-square-foot rates use the nominal face (brick plus 3/8-inch joint). That is why counting from the bare brick dimensions alone overestimates the number needed.