Brick Calculator: Bricks, Mortar and Sand for a Wall

How it works

bricks per sq ft = 144 ÷ [(brick length + joint) × (brick height + joint)] (in); modular units use their nominal size on the 4 in module (modular 8 × 2 2/3 in = 6.75 per sq ft) · bricks = net wall area × bricks per sq ft × wythes × (1 + header-bond factor) × (1 + waste) · mortar per brick = depth × [(l + j)(h + j) − l × h] · bags ≈ standard-brick equivalents ÷ 144 (70 lb masonry cement) or ÷ 36 (80 lb premix)

Each brick plus its share of mortar covers a rectangle of wall face equal to the brick length plus one joint by the brick height plus one joint. Dividing the net wall area (gross area less doors and windows) by that rectangle gives the bricks for one wythe. Modular units (modular, engineer, closure, Norman, Roman, utility) are laid on the 4 in module, so the Brick Industry Association counts them by their nominal size: a modular brick plus joint takes 8 in of length and three courses rise 8 in (the mason adjusts the bed joints to hit that), so each brick covers 8 × 2 2/3 = 21.33 in², 6.75 bricks per square foot (675 per 100 sq ft, BIA Table 4) or 72.7 per m². Non-modular bricks (standard, queen, king, UK, Australian, custom) use their actual size plus the joint. Two wythes double the count, and header bonds add the net factors published by the Brick Industry Association: 1/6 for common bond with headers every sixth course, 1/3 for Flemish bond and 1/2 for English bond. Waste is added last; BIA suggests at least 5% for brick, and 10% is a common allowance for cuts at corners and openings plus breakage. Mortar volume is the joint area around each brick times its bed depth, plus a solid collar joint for double-wythe walls and 15–25% mortar waste. Bags use the manufacturer coverage for a standard brick, scaled to your brick’s joint volume: roughly 144 bricks per 70 lb bag of masonry cement mixed with 240 lb of sand (about seven bags per 1,000 bricks) or about 36 bricks per 80 lb bag of premixed mortar. Actual counts vary with the bond, the number of cut bricks at corners and openings, and the mason.

Worked example

A 20 × 8 ft single-wythe wall is 160 sq ft. A modular brick laid on the 4 in module takes a nominal 8 × 2 2/3 in of wall face (brick plus 3/8 in joint), 21.33 in², so 144 ÷ 21.33 = 6.75 bricks per sq ft and 160 × 6.75 = 1,080 bricks. With 10% waste that is 1,188 bricks to order. The joints hold 14.0 in³ of mortar per brick, 8.74 cu ft net or 10.5 cu ft with 20% mortar waste, and the coverage rule gives 1,046 standard-brick equivalents ÷ 144 = 8 bags of masonry cement plus 1,920 lb of sand. The wall is 36 courses of 30 bricks.

Sources: BIA Technical Note 10, Dimensioning and Estimating Brick Masonry · QUIKRETE Masonry Cement data sheet (bag yield) · QUIKRETE Mason Mix data sheet (bricks per 80 lb bag)

Frequently asked questions