Free Building Materials Calculator
Calculate quantities for concrete, bricks, timber, plasterboard, tiles, and paint. Our free calculator includes Australian industry-standard waste allowances to help you order the right amount for your project.
Calculate concrete volume for slabs, footings, and columns
Floor slabs, driveways, paths
Common: 0.1m (100mm) for slabs
Waste allowance: 7% (typical range: 5-10%)
Enter dimensions above to calculate Concrete quantities
How to Use This Calculator
1. Select Material Type
Choose from six material categories: concrete, bricks/blocks, timber framing, plasterboard, tiles, or paint. Each has specific calculation modes.
2. Choose Calculation Mode
Select the appropriate mode for your application. For example, concrete offers slab, footing, and column calculations with different input requirements.
3. Enter Dimensions
Input your measurements in metres. For walls, you can add openings (doors and windows) to deduct from the total area.
4. Review Results
Get your order quantity with waste allowance included. The breakdown shows base quantity, waste amount, and total required.
Understanding Waste Allowances
Construction projects always require more materials than the calculated base quantity. Our calculator includes industry-standard waste allowances:
- Concrete: 5% for spillage, over-excavation, and formwork variations
- Bricks/Blocks: 5% for breakages and cutting
- Timber: 10% for cutting, defects, and miscounts
- Plasterboard: 10% for cutting and damage
- Tiles: 10% for cutting, breakages, and pattern matching
- Paint: 10% for coverage variations and touch-ups
You can toggle waste allowances on or off depending on your needs. Complex layouts or inexperienced installation may require additional allowance.
How the calculation works, and what it assumes
The maths per material
- Concrete: length × width × depth for slabs and strip footings, or the column formula for piers, giving cubic metres. Round up to the truck or bag size you order in.
- Bricks and blocks: wall area minus door and window openings, multiplied by the per-m² count for the size you pick: 50 standard, 36 modular or 12.5 concrete blocks.
- Timber framing: studs at 450mm or 600mm centres across the wall length, plus top and bottom plates, on a 2.4m wall height you can change. Joists and rafters use the span and spacing you enter.
- Plasterboard: wall or ceiling area divided by the sheet you choose (2400, 3000 or 3600 × 1200mm), rounded up to whole sheets.
- Tiles: area divided by the tile format (300 × 300 up to 600 × 600 and 300 × 600mm). Diagonal or herringbone layouts need extra cutting allowance on top.
- Paint: surface area × coats ÷ 12m² per litre, then matched to standard tin sizes.
Assumptions and regional variance
- Standard 10mm mortar joints, single-skin walls and square-set openings. Double-brick construction, common in WA, doubles the brick count per metre of wall.
- Waste allowances are typical percentages, not maximums. Small, cut-heavy rooms, feature patterns and inexperienced crews push waste higher.
- Sheet, tile and brick sizes vary by supplier and by state. The calculator lists the common formats. Check what your local yard stocks before you order.
- Quantities are independent of location, but prices are not. Use the construction cost calculator to see how rates differ between Sydney, Melbourne, Brisbane, Perth and Adelaide.
- The tool does not replace an engineer's specification. Slab thickness, reinforcement, footing size and framing member sizes must come from the approved plans.
Material take-off from plans is a core skill in the Certificate IV in Building Project Support (Estimator) and the Certificate IV in Building and Construction.
Materials calculator FAQs
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