Brick Calculator

Estimate how many bricks a wall needs, with a wastage allowance.

cm
cm
%
Bricks needed (with wastage)
Bare minimum
Bricks per m²
Spare for cuts
Brick face

Single-skin estimate including mortar joints. Double walls roughly double the count; mortar is a separate calculation.

Counting bricks by area

Each brick covers its face area plus the mortar joint around it. Divide the wall area by that effective brick size and you have the number of bricks for a single-skin wall.

bricks = area ÷ ((length + joint) × (height + joint)) × (1 + wastage)

Entering the brick size with the joint included keeps the estimate honest. A standard format works out to roughly sixty bricks per square metre, but the calculator adapts to whatever size you give it.

Worked example

A 10 m² single-skin wall with bricks 22.5 × 7.5 cm including mortar (about 59 bricks per m²) needs roughly 593 bricks bare, or about 652 with 10% added for cuts and breakages.

Ordering with confidence

Bricks are bought in packs and run as one batch for colour consistency, so it pays to order enough — including wastage — in a single go. A small surplus also leaves matching bricks for future repairs.

On-site notes

  • Include the joint. Mortar is part of each brick’s footprint.
  • Double for two leaves. Cavity walls need roughly twice the count.
  • Match the batch. Ordering together keeps the colour even.

Frequently asked questions

Why include the mortar joint in the brick size?
Because each brick effectively occupies its own size plus the surrounding mortar. Using the face size with the joint added gives a realistic count for the wall area.
How many bricks per square metre?
For a standard single-skin wall it is around 59–60 per m² (about 55 per yd²). The calculator works it out from the brick size you enter, so other formats are covered too.
What about a double-skin or cavity wall?
A double thickness roughly doubles the bricks. If you are building two leaves, calculate one and double it, or enter twice the area.
How much wastage should I allow?
Around 5–10% is typical to cover cuts, breakages and the odd reject. Add more for lots of openings, curves or decorative bonds.