Brick / Block Calculator
Estimate how many bricks or blocks you need for a wall — accounting for the mortar joint, an openings allowance for doors and windows, and a wastage percentage for cuts and breakage, in metric or imperial units.
Input
Metric enters the wall in metres and the brick/block in millimetres; imperial uses feet and inches.
Total wall length (metres in metric, feet in imperial).
Wall height (metres in metric, feet in imperial).
Total area to subtract for doors and windows (square metres in metric, square feet in imperial). Leave blank if none.
Exposed face length of a single brick or block (millimetres in metric, inches in imperial).
Exposed face height of a single brick or block (millimetres in metric, inches in imperial).
Mortar bed/perpend joint thickness (millimetres in metric, inches in imperial).
Extra units for cuts, breakage and future repairs (5% is typical; use more for a complex layout).
Output
| Metric | Value |
|---|---|
| No data yet | |
One-line overview of net wall area and units needed (with wastage).
Guides
The Brick / Block Calculator estimates how many bricks or blocks you need to build a wall. Enter your wall dimensions and the brick or block's face size and it works out the gross and net wall area, the effective coverage of a single unit (including the mortar joint), and how many units to order — with and without a wastage allowance. It supports metric (m / mm) and imperial (ft / in) input.
How to use it
- Pick your unit system — metric (wall in metres, brick/block in millimetres) or imperial (wall in feet, brick/block in inches).
- Enter the wall length and height.
- Optionally enter an openings area to subtract the total area of doors and windows from the wall.
- Enter the brick/block's exposed face length and height, and the mortar joint thickness between units.
- Set a wastage percentage for cuts, breakage and future repairs.
Results update instantly. The table shows gross wall area, openings subtracted, net wall area, effective unit area, units needed (with and without wastage), and extra units for waste. A one-line summary is provided for quick copying.
How is the unit count calculated?
Each brick or block is treated as occupying an effective grid cell of (unit length + mortar joint) x (unit height + mortar joint) — the same way tile calculators account for the grout gap. Dividing the net wall area by this cell area gives the base unit count, then the wastage percentage is applied and the result rounded up.
What mortar joint should I use?
A standard mortar bed and perpend joint is typically 10mm (3/8in) for brick, though it varies by masonry unit and local practice. Set it to 0 to estimate coverage from the bare unit face alone.
How much wastage should I add?
5% is a common allowance for a straightforward running-bond wall. Add more for a complex layout with lots of cuts (corners, openings, curved sections), or if you want spare units on hand for future repairs.
Does it account for door and window openings?
Yes — enter the total area of any openings and it's subtracted from the gross wall area before the unit count is calculated, so you don't order bricks for space you won't be filling.
Is my data private?
Completely. Every calculation runs entirely in your browser. Nothing you type is uploaded, stored or sent to a server, so you can estimate as many walls as you like in total privacy.
More ways to use this tool
REST API
curl -X POST https://api.iotools.cloud/v1/tool/brick-block-calculator \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"unitSystem": "metric",
"wallLength": "5",
"wallHeight": "3",
"openingsArea": "3.5",
"unitLength": "215",
"unitHeight": "65",
"mortarJoint": "10",
"wastagePct": "5"
}'Swap in your own key from your account. The tool's fields are the body — no wrapper.
Ask an AI agent
Use the IOTools `brick-block-calculator` tool (Brick / Block Calculator) on this input:
YOUR_INPUT_HEREPaste this at any agent connected to the IOTools MCP server, then add your input.
Embed widget
<iframe
src="https://iotools.cloud/embed/brick-block-calculator/"
width="100%" height="520" frameborder="0" scrolling="no" loading="lazy"
title="Brick / Block Calculator — iotools.cloud"
sandbox="allow-scripts allow-forms allow-same-origin allow-downloads allow-popups allow-popups-to-escape-sandbox"
allow="clipboard-write"
style="width:100%;border:1px solid #e5e7eb;border-radius:12px;overflow:hidden"></iframe>
<script src="https://iotools.cloud/embed.js" async></script>Drop this into your own page — free, no key required, just a link back.
| Cost per call | From 5 credits |
|---|