Answer: Enter your values and the Brick Calculator returns the exact result instantly — formula, worked example, and a plain-English explanation are included below the tool.
Bricks, mortar bags, and cost estimate for any wall
This brick calculator tells you how many bricks and bags of mortar to buy for any wall. Enter the wall dimensions (or a known wall area), choose your brick size, set a waste factor, and it returns bricks required, 80 lb mortar bags, and a material cost estimate. It works for face brick, structural brick veneer, and garden walls.
Brick is sold by the thousand, and mortar by the bag, so an accurate takeoff saves both extra trips and pallets of surplus. The core math is bricks = wall area × bricks per square foot, where bricks-per-sq-ft depends on the bedded face size of the brick plus the mortar joint. Openings such as doors and windows should be subtracted from the wall area before you enter it.
Bricks per square foot comes from 144 ÷ (bedded width × bedded height in inches), using the face dimensions plus a standard ⅜ inch mortar joint. For modular brick bedded at 8 × 2⅝ inches, that is 144 ÷ 21 = 6.86, rounded to 7 bricks per square foot. Queen size runs about 5.7 per sq ft and King about 4.6, which is why larger bricks cut both the brick count and the number of joints to tool.
Mortar is estimated at roughly 37 modular bricks per 80 lb bag of premix — an 80 lb bag yields about 0.72 ft³ of mortar, enough for 35–40 modular bricks. Choose type N mortar for veneer and type S where higher flexural strength is specified. Waste of 5–10% covers cuts, breakage, and color blending between cubes.
The table below compares the three sizes this calculator supports, their bedded dimensions with a ⅜ inch joint, and the resulting bricks per square foot. Modular brick aligns at three courses per 8 inches, which simplifies layout with standard lintels and rowslock.
| Brick size | Bedded face (with ⅜ in joint) | Bricks per sq ft | Bricks per 80 lb mortar bag |
|---|---|---|---|
| Modular | 8 × 2⅝ in | 6.86 → 7 | 35–40 |
| Queen | 7⅝ × 2¾ in | ≈ 5.7 | ~45 |
| King | 9⅝ × 2¾ in | ≈ 4.6 | ~55 |
Order the full quantity at once: bricks vary slightly in color between manufacturing runs, so a top-up order may not match. Blend from multiple cubes as you lay rather than working cube-by-cube, and keep the brick dry before use — saturated brick sucks water from the mortar and weakens the bond.
For the worked example, a 20 × 8 ft wall (160 sq ft) in modular brick needs 160 × 6.86 = 1,097 bricks, or 1,207 with 10% waste, plus about 30 bags of mortar. At $500 per thousand that is roughly $605 of brick. Plan courses with a story pole, maintain consistent joint thickness, and tool the joints when a thumbprint holds an impression.
Subtract openings before entering your area: doors, windows, and louvers all reduce brick count, but each opening adds cuts and a lintel, so the waste factor should rise slightly on heavily fenestrated walls. Arches and radiused work add more still — each tapered cut wastes material, and 15% waste is not unreasonable for curved garden walls.
Scaffolding, flashing, and wall ties belong in the plan even though they are not brick. Veneer over wood framing requires corrugated ties at a code-specified spacing (typically every 16 inches vertically and 24 horizontally, though local code governs), weep holes at the base, and through-wall flashing above openings. These details are cheap during construction and expensive to retrofit, so they are worth confirming before the first course goes down.
Weather and workmanship affect the result as much as the count. Brickwork should not be laid below about 40°F (4°C) without cold-weather protection, because mortar needs time and warmth to cure; hot, dry weather calls for pre-wetting brick so they do not steal water from the joint. Consistent joint thickness — usually ⅜ inch — keeps courses level and the per-square-foot math honest.
How many modular bricks are in a square foot?
With a standard ⅜ in mortar joint, a bedded modular brick measures 8 × 2⅝ inches, giving 144 ÷ 21 = 6.86 — round to 7 bricks per square foot.
How much mortar does a bag make?
An 80 lb bag of premixed mortar yields about 0.72 ft³, enough to lay roughly 35–40 modular bricks. A 3,000-brick job needs 75–85 bags.
How many bricks do I need for a 100 sq ft wall?
About 686 modular bricks before waste (100 × 6.86); order 750–760 with a 10% waste factor, plus roughly 19–20 bags of mortar.
How much waste should I add for brick?
5–10% is standard, covering cuts, breakage, and blending. Use 10% for walls with many openings or intricate detailing.
Which mortar type should I use?
Type N for non-load-bearing veneer and above-grade exterior work; type S where higher strength is needed, such as structural or below-grade masonry.