CalcPenguin

Brick Calculator

How many standard 9 × 4.5 × 3 inch bricks a wall needs, leaving out doors and windows and adding a little for breakage.

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ft
ft
sq ft

Area to leave out. A standard door is about 3 × 7 ft = 21 sq ft.

in

3/8 inch (about 10 mm) is usual.

%

Bricks

1,580

Masonry volume
134.3 cft
Bricks per cubic foot
11.2

A 20 × 10 ft wall, 9 inches thick, needs about 1,580 standard 9 × 4.5 × 3 inch bricks, including 5% for breakage.

How it's worked out

  1. Wall area20 × 10 − 21 sq ft179 sq ft
  2. Volume179 sq ft × 9 in ÷ 12134.25 cft
  3. Bricks per cft with mortar1,728 ÷ (9.375 × 4.875 × 3.375)11.2
  4. Bricks with breakage134.25 × 11.2 × 1.051,580

How bricks are counted

Bricks per cft = 1,728 ÷ ((9 + j) × (4.5 + j) × (3 + j)), where j is the mortar joint in inches

The wall volume in cubic feet is the area, minus openings, times the thickness. Multiply by bricks per cft and add breakage.

Worked example

A 20 × 10 ft wall, 9 inches thick, with one 3 × 7 ft door, is 179 sq ft and 134.25 cft. With 3/8-inch joints that's 11.2 bricks per cft, about 1,504 bricks, or 1,580 with 5% for breakage.

Questions people ask

How many bricks are in one cubic foot?

About 11.2 standard Pakistani bricks (9 × 4.5 × 3 inches) with a 3/8-inch mortar joint, or about 1,120 bricks per 100 cft.

How many bricks for a 9-inch wall?

Each square foot of a 9-inch wall is 0.75 cft, so about 8.4 bricks. A 20 × 10 ft wall with no openings takes about 1,681 bricks before breakage.

Does this include mortar?

The joint is counted in each brick's space, so the count is right for a mortared wall. Mortar itself (cement and sand) is a separate quantity.

Formula and rules last checked 25 October 2026Written and tested by the CalcPenguin teamReport a problem