How Much Do I Need?

Brick Calculator

How many bricks do I need?

Enter the length and height of the wall, the size of one brick and the mortar joint. The calculator works out how many bricks fill the wall face, multiplies by the number of layers, and adds a waste allowance.

Units
Wall

A single-skin garden wall is 1; a solid double-thickness wall is 2.

For L-shaped or irregular spaces, split them into rectangles and add each one.

Bricks

US modular brick: 7 5/8 in. UK standard: 215 mm.

Usually 3/8 in (0.375 in) or 10 mm.

For broken bricks and cuts. 5–10% is common.

Cost (optional)

Add the price to see an estimated total.

Results update as you type.

Your estimate

Bricks to buy

576 bricks

6.86 per ft² of wall face, 1 layer, including 5% waste.

Estimated amount to buy

Bricks
576

Calculated quantity (no waste)

Wall face
80 ft²
Bricks per unit of wall
6.86 per ft²
Bricks
548.57
How this was calculated
  1. Wall face = 20 ft × 4 ft = 80 ft²
  2. Space per brick = (7.625 in + 0.375 in) × (2.25 in + 0.375 in) = 21 in², so 6.86 per ft²
  3. Bricks = 80 ft² × 6.86 per ft² = 548.57
  4. With 5% waste = 548.57 × 1.05 = 576, rounded up to 576
  • Openings: subtract windows and doors by adding the wall as several rectangles around them.
  • Mortar, wall ties, a damp-proof course and foundations are extra. Load-bearing and tall walls need proper design and may need approval.

How the brick calculation works

  1. Wall face = length × height. Add extra rectangles for walls with steps or piers.
  2. Space per brick = (brick length + joint) × (brick height + joint). Each brick takes up its own face plus one joint along its top and one at its end.
  3. Bricks = wall face ÷ space per brick × number of layers.
  4. Add waste and round up.

With UK standard bricks (215 × 65 mm) and 10 mm joints that gives about 59 bricks per m², close to the usual "60 per m²". With US modular bricks (7 5/8 × 2 1/4 in) and 3/8 in joints it gives about 6.9 per ft². Trade tables often quote 6.75, because modular brick courses are designed to rise exactly 8 in every three courses.

Rounding rules

  • Bricks are rounded up to whole bricks after the waste allowance.
  • Bricks are often sold in packs or pallets; round up again to your supplier's pack size.

Before you build

A garden wall needs a proper concrete footing below the frost line, and taller or longer walls may need piers, movement joints or reinforcement. Check local building rules before building boundary or retaining walls.