Bricklaying Calculator

Calculate how many bricks and how much mortar you need. Choose your bond type, enter wall dimensions, and deduct openings.

Ordering the right number of bricks saves money and avoids the frustration of mid-project shortages or expensive surplus. A standard UK brick measures 215mm x 102.5mm x 65mm, and the number you need per square metre depends on whether you are building a half-brick or full-brick wall, and on the bond pattern chosen.

Stretcher bond (the most common for cavity walls) uses approximately 60 bricks per square metre. Flemish or English bond, used for solid walls, uses around 120 per square metre because every other course shows the brick end-on. Mortar volume depends on the joint thickness, typically 10mm, and must be factored in alongside a 5–10% wastage allowance.

The Brick Development Association reports that around 1.7 billion bricks are produced in the UK each year, with a further 500 million imported to meet demand (BDA). Getting the quantity right first time prevents delivery delays and keeps your bricklayer on schedule.

How this calculator works

  1. Enter the wall length, height, and bond type (stretcher, Flemish, or English).
  2. Deduct any openings for doors and windows.
  3. The tool calculates the number of bricks, bags of mortar, and includes a wastage allowance.

Written by the CalcStack team · Last updated April 2026

Door ~1.9m², Window ~1.5m²

Frequently asked questions

How many bricks do I need per square metre?▾
For a standard single-skin wall in stretcher bond using standard UK bricks (215 x 102.5 x 65mm with 10mm mortar joints), you need approximately 60 bricks per square metre. Flemish bond needs about 79 and English bond about 89.
What size are standard UK bricks?▾
Standard UK bricks are 215mm long x 102.5mm wide x 65mm high. With 10mm mortar joints, the coordinating size is 225 x 112.5 x 75mm. Engineering bricks are the same dimensions but denser and stronger.
How much mortar do I need?▾
For stretcher bond, allow approximately 25kg of ready-mixed mortar per square metre of brickwork. This assumes 10mm mortar joints. Flemish and English bonds use more mortar due to additional header courses.
What wastage percentage should I allow?▾
Allow 5% for standard work with careful cutting, 7.5% for typical projects, and 10% for complex walls with many cuts, angles, or if you are less experienced. It is better to over-order slightly than to run short.
What is stretcher bond?▾
Stretcher bond is the most common brickwork pattern where each brick is laid lengthways (showing the stretcher face) and offset by half a brick from the row above. It is used for single-skin walls and cavity wall outer leaves.
What is the difference between flemish and english bond?▾
Flemish bond alternates headers (short face) and stretchers in each course. English bond alternates full courses of headers and stretchers. Both create stronger, thicker walls than stretcher bond but use more bricks.
How do I calculate for openings?▾
Deduct the area of doors, windows, and other openings from the total wall area. Measure the width and height of each opening. Remember to add a few extra bricks for cutting around openings.
What mortar mix should I use?▾
For general purpose above-ground brickwork, use a 1:1:6 mix (cement:lime:sand) or 1:5 cement:sand with plasticiser. For below ground or exposed conditions, use a stronger 1:0.5:4.5 mix.
How many bricks come in a pack?▾
Standard brick packs typically contain 400 or 500 bricks per pallet. Engineering bricks often come in packs of 400. Check with your supplier as pack sizes vary by manufacturer.
Should I order extra bricks?▾
Yes, always order extra. Beyond wastage, keep spare bricks for future repairs and matching. Different firing batches can have slight colour variations, so ordering all bricks at once ensures consistency.

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© 2026 CalcStack — a Flavoureak UK Ltd product. Quantities are estimates — always verify with your supplier.