Using the Brick & Mortar Calculator
Subtract the total area of openings from the wall face and enter thickness in millimetres. Brick dimensions also use millimetres. The module approximation adds a joint allowance to each dimension, then estimates how many modules occupy the wall volume.
Worked example
Use the example inputs below to reproduce this result. These are the form's starting values, not recommended targets. Changing your inputs updates your result above; this worked example stays fixed for comparison. Results are rounded for display.
Example inputs
- Wall length (m)
- 5
- Wall height (m)
- 3
- Wall thickness (mm)
- 200
- Total opening area (m²)
- 2
- Brick length (mm)
- 190
- Brick width (mm)
- 90
- Brick height (mm)
- 90
- Mortar joint allowance per module (mm)
- 10
- Brick waste (%)
- 5
- Price per brick (your currency)
- 10
Example result
- Net wall volume (m³)
- 2.6
- Theoretical brick count
- 1,300
- Bricks to buy incl. waste
- 1,365
- Wet mortar estimate (m³)
- 0.5993
- Brick material cost
- 13,650
Method and assumptions
Net wall volume = (length × height − openings) × thickness. Approximate modules use (brick length + joint) × (brick width + joint) × (brick height + joint). Brick purchases round up after waste. Wet mortar = net wall volume minus theoretical brick solid volume, without waste. This volume model does not design bonds, structural walls, dry-mix quantities or exact cutting layouts.
Reference: gobrick.com — method and further reading
Check the geometry against the available space
A stair calculation can distribute height evenly yet still require more horizontal space than is available. Compare the calculated run with the actual opening and layout. The simplified geometry does not check landings, headroom or every construction requirement. Those constraints need to be resolved before dimensions are treated as a buildable design.
Common question
Can the wet mortar volume tell me how many cement bags to buy?
Not by itself. A dry material mix requires additional assumptions about mix ratio, bulking, moisture and material density. The tool only subtracts the theoretical solid brick volume from net wall volume and does not convert that wet volume into cement or sand purchases.