About Brick, Block & Mortar Calculator
The brick and mortar calculator answers "how many bricks do I need" for a wall of any size. Enter the wall length and height (or the face area directly), deduct up to three door or window openings, pick the masonry unit, and the tool returns the number of bricks or concrete blocks including a waste allowance, along with the premixed mortar bags, masonry sand, and pallets to order.
Presets cover the common units: US modular brick at 6.86 per ft², queen and king oversize brick, the UK/metric standard brick at 60 per m² for a half-brick wall, and 8, 6 and 4 in concrete masonry units (CMU) at 1.125 per ft². A custom option computes the coverage of any unit size from its face dimensions and mortar joint thickness, so the same take-off works for pavers, jumbo brick, or non-standard block.
How It Works
- Choose imperial or metric units and enter the wall length and height, or the gross face area directly, then add up to three openings (doors, windows) to deduct.
- Select the masonry unit. Presets carry the published units-per-area figure; the custom option computes it as 1 / ((L + j)(H + j)) from the unit face size L x H and joint thickness j.
- The unit count is net area x units-per-area x wythe multiplier x (1 + waste%). Double wythe doubles the brick count for a two-leaf solid wall.
- Mortar is estimated from published laying rates (about 7 bags of 80 lb premixed mortar per 1000 bricks and 3 bags per 100 blocks); custom units use the joint volume per unit at a yield of ~1.15 ft³ of placed mortar per bag.
- Masonry sand is taken as one cubic yard per 7.5 bags at 1.35 short tons per cubic yard, and pallets assume 500 bricks or 90 blocks per cube.
Worked Example
A 10 ft x 10 ft garden wall in US modular brick, single wythe, with 10% waste: the net area is 100 ft² and modular brick lays at 6.86 per ft², so the count is 6.86 x 100 x 1.1 = 754.6, rounded up to 755 bricks — two pallets at 500 per cube. Mortar at 7 bags per 1000 bricks is 755 x 0.007 = 5.3, so order 6 bags of 80 lb premixed Type S or N, with about 0.7 yd³ (1 ton) of masonry sand if mixing from masonry cement. The same wall in 8x8x16 CMU with no waste needs 100 x 1.125 = 112.5, i.e. 113 blocks and 113 x 0.03 = 3.4 (order 4) bags of mortar.
Formulas
- Units per area from unit dimensions
n = 1 / ((L + j) * (H + j))- Unit count
N = A_net * n * w * (1 + waste/100)- Mortar bags (published rates)
bags = N * r, r = 0.007 (brick) or 0.03 (CMU)- Mortar bags (custom units, joint-volume model)
bags = N * [((L + j)(H + j) - L*H) * W] / Y- Masonry sand
V_sand = bags / 7.5 (yd³), m_sand = 1.35 * V_sand (tons)
Standards & References
- ASTM C216 / C652 facing brick dimensions
- ASTM C90 loadbearing concrete masonry units
- BS EN 771-1 / BS 4729 UK clay masonry units
- ASTM C270 mortar for unit masonry (Type N / S)
- TMS 402/602 building code requirements for masonry structures
Frequently Asked Questions
How many bricks do I need per square foot of wall?
A US modular brick (7-5/8 x 2-1/4 x 3-5/8 in with a 3/8 in joint) lays at about 6.86 bricks per square foot of wall face in a single-wythe wall, so a quick estimate is 7 bricks per ft² before waste. Queen brick covers more area at 5.76 per ft² and king brick at 4.8 per ft². Multiply the net wall area by the rate, then add 5-15% waste for cuts and breakage.
How many bricks are there per square metre?
A UK/metric standard brick of 215 x 65 x 102.5 mm laid with a 10 mm joint works out to 60 bricks per square metre for a half-brick (single-leaf, 102.5 mm) wall. A one-brick solid wall of 215 mm thickness needs double that, 120 per m². These figures already include the mortar joints, so multiply by the net wall area and add waste.
How many concrete blocks do I need for a wall?
A standard 8x8x16 nominal CMU covers a 16 x 8 in module including its 3/8 in joints, which is 1.125 blocks per square foot (about 12.1 per m²). Divide the net wall area by the module — for example a 100 ft² wall needs 112.5, so order 113 blocks plus waste. The 6 in and 4 in blocks share the same face size, so the count per area is identical; only the wall thickness changes.
How much mortar do I need per 1000 bricks or 100 blocks?
The traditional estimating rules are about 7 bags of masonry cement or 80 lb premixed mortar per 1000 modular bricks, and about 3 bags per 100 concrete blocks, both with roughly 1 cubic yard of masonry sand per 7-8 bags when mixing on site. This calculator applies those rates to the rounded unit count and, for custom unit sizes, estimates the joint volume per unit directly at a placed yield of about 1.15 ft³ per bag.
What waste percentage should I add for brick and block?
A 10% waste allowance is the common default for brickwork, covering cutting at corners and openings, broken units, and colour-matching rejects. Simple long runs of block wall can work at 5%, while walls with many openings, piers, or raked bonds may justify 15%. Buying the full estimate in one batch also avoids colour variation between production runs.
What is the difference between a single and double wythe wall?
A wythe is one vertical leaf of masonry one unit thick. A single-wythe (half-brick) wall is the usual veneer or garden wall; a double-wythe wall has two leaves bonded together for a solid, roughly 8 in or 215 mm thick wall and needs twice as many bricks per square foot of face. The double option in this tool applies to brick only — CMU walls are normally a single wythe of wider block.
How many bricks or blocks come on a pallet?
Brick cubes are commonly banded around 500 modular bricks per pallet (manufacturers range from about 400 to 525), and standard 8 in CMU is typically stacked 90 blocks per pallet (72-96 depending on plant and block size). The tool uses 500 and 90 to convert the order quantity into pallets, rounding up so you can check truck loads and site storage.