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Brick & Block Calculator
Estimate how many bricks/blocks you need. Enter dimensions in millimetres (mm). We account for joint thickness, single/double skin, openings, and optional 5% wastage.
Typical brick length ~215mm. Use actual size.
Typical brick height ~65mm. Use actual size.
10mm is common; adjust to suit your detail.
Double skin will multiply the quantity by 2.
Auto-calculated: wall area minus openings.
Include 5% Wastage

Openings (optional)

Enter opening width × height (mm). Openings area will be subtracted.
Total openings area: 0.00 m²
| Wall area (gross): 0.00 m²

Units per m² (net)

–
Based on unit size + joint

Total Bricks/Blocks Required

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Excludes wastage
Happy with the results? View our Bricks View our Blocks

How to use this calculator

  1. Enter your brick/block length and height (mm).
  2. Enter the wall length and wall height (mm).
  3. Add any openings (mm) and we’ll subtract them from the wall area.
  4. Adjust the mortar joint (10mm by default) if needed.
  5. Choose single or double skin.
  6. Toggle 5% wastage to allow for cuts and breakages.

FAQs

How does the calculator work?

We convert your wall size to square metres and subtract openings. Then we divide by the face area of one unit including the mortar joint: (length + joint) × (height + joint). Double skin multiplies by 2. If wastage is enabled, we add 5% before rounding up.

What mortar joint should I use?

10mm is common for brickwork. Some blocks or systems specify different joint sizes — always follow the product datasheet or your specification.

Does this account for openings like doors and windows?

Yes — enter each opening’s width and height in millimetres and the tool will subtract their combined area.

What about bond patterns, piers or returns?

These can affect cutting and wastage. This tool gives a general estimate. Complex details may require additional allowance.

Is it suitable for both bricks and blocks?

Yes — enter the actual unit length and height for your brick or block, set the joint, and the calculator will estimate the quantity.

How many bricks per m² on average?

As a rule of thumb with 10mm joints: standard UK bricks (~215×65mm) ≈ 60 bricks/m² for single skin. Common blocks (~440×215mm) ≈ 10–11 blocks/m². Your actual result may differ based on sizes and joint thickness.

How much mortar will I need?

This varies with joint thickness and wastage. A rough guide for brickwork is about 0.018–0.03 m³ per m² (≈18–30 litres/m²). Always check your specification and allow extra for cuts and site conditions.

Disclaimer: The information on this page is a general guide only and is not tailored advice from a qualified professional. Gilmore Building Supplies aims to keep content current but cannot accept liability for outdated or incomplete information. There are many variables when calculating brick and block quantities; please treat this calculator as an estimate and confirm final requirements with your designer or contractor. Always check with your architect/engineer for compliance with NHBC or Building Regulations.