Brick Calculator — How Many Bricks Do I Need?

This calculator determines the number of bricks needed by calculating the net wall area (after deducting door and window openings), then multiplying by the bricks-per-square-metre rate for your chosen bond type.

The formula

Bricks = (Wall area - Openings) × Bricks per m² × Wastage factor

Rates used

• Stretcher bond (half brick): 60 bricks per m² — standard cavity wall leaf
• English bond (full brick): 120 bricks per m² — alternating stretcher and header courses
• Flemish bond (full brick): 120 bricks per m² — alternating stretchers and headers in each course

These rates are based on the standard UK brick size (215 × 102.5 × 65mm) with 10mm mortar joints, giving a coordinating size of 225 × 75mm face area. This is the industry standard calculation method used across UK construction. See our full standard UK brick size and dimensions reference for coordinating sizes and bricks-per-m² by bond. If you are building the outer leaf of a cavity wall, remember the ties that hold the two leaves together — our wall ties calculator works out how many wall ties per m² of brickwork you need to Approved Document A. If you are building a house extension, our brick and block extension wall calculator estimates the full cavity-wall package — bricks, blocks, insulation, wall ties, lintels and cavity closers — in one pass.

Mortar estimate

For a half-brick (stretcher bond) wall, allow approximately 0.022 m³ of mortar per m² of wall face — roughly 0.02 m³/m² of net joint volume plus a small waste allowance for 60 bricks/m² with 10mm joints. For full-brick walls (English/Flemish bond, one brick thick) this doubles to about 0.044 m³ per m². Use our Mortar Calculator for a detailed breakdown of cement and sand quantities.

Standards

Brick sizes conform to BS EN 771-1:2011+A1:2015. Masonry design in the UK now follows Eurocode 6 (BS EN 1996), which superseded the former BS 5628 code of practice when the BS 5628 suite was withdrawn by BSI on 31 March 2010.