Flooring & Tile
Flooring Calculator
Enter your room dimensions in metres to get the square metres of flooring to buy and the number of boxes, with a wastage allowance for cuts and spares.
Formula tested · Local units · No sign-up
Project inputs
Enter measurements
Use your preferred units. Results update automatically.
Show the calculation methodFormula, conversions, rounding, and assumptions+
Room area = length × width in square metres — a 6 m × 4 m open-plan area is 24 m². For L-shaped spaces, add the rectangles and use direct-area mode.
A wastage allowance is added on top (default 8% for a straight lay; more for diagonal or herringbone), then the total is divided by the coverage printed on the box — commonly around 2–2.5 m² for laminate or hybrid plank — and rounded up to whole boxes, because flooring is sold in sealed boxes.
Real-world example
Worked example: 6 m × 4 m living area, hybrid plank, 8% wastage
- Room area: 6 × 4 = 24 m².
- Add 8% wastage: 24 × 1.08 = 25.92 m² to purchase.
- Boxes at 2.5 m² per box: 25.92 ÷ 2.5 = 10.37.
- Round up to whole boxes: 11 boxes.
Buy 11 boxes (27.5 m²). At an example GST-inclusive price of $60 per box, that's $660.00 — advertised Australian prices normally already include 10% GST.
Before you start
How to measure
- Measure the room in metres wall to wall; laminate and hybrid floors need an expansion gap at the perimeter, usually covered by skirting or scotia, so measure to the wall, not the skirting face.
- Take the m² coverage per box from the label; it varies by plank size and brand, so 2.5 m² is only a typical figure.
- For open-plan areas flowing through doorways, measure each zone and add the areas in direct-area mode.
Local guidance
Notes for Australia
- The Australian market is dominated by laminate and 'hybrid' (rigid-core vinyl) plank, priced per m² but sold by the box with the m² coverage on the label.
- Australian conditions vary from humid tropics to dry heat — follow the manufacturer's acclimatisation and expansion-gap instructions for your climate zone.
- GST is 10% and advertised retail prices normally include it; trade and online-direct prices are sometimes ex-GST — check before comparing.
Quick reference
Typical wastage allowance by laying pattern (planning values)
| Pattern | Typical allowance |
|---|---|
| Straight lay, regular room | 8% |
| Straight lay, many doorways/alcoves | 10% |
| Diagonal lay | 12–15% |
| Herringbone | 15–20% |
Planning values only — your installer and the room's shape determine the real allowance.
Good to know
Common mistakes to avoid
- Buying the exact room area with no wastage — every row ends in a cut, and spare planks from the same batch are the only clean repair.
- Ignoring the expansion gap and butting planks hard to the wall, which causes peaking in hot weather.
- Comparing a GST-inclusive advertised price against an ex-GST trade quote.
- Skipping acclimatisation in climates with big humidity swings — check the manufacturer's instructions.
Need help?
Frequently asked questions
How many boxes for a 5 m × 3 m bedroom?
5 × 3 = 15 m²; with 8% wastage that's 16.2 m². At 2.5 m² per box, 16.2 ÷ 2.5 = 6.48, so buy 7 boxes — and check the coverage on your actual box, which varies by product.
What's the difference between laminate and hybrid flooring?
Laminate has a timber-fibre core; hybrid is a rigid vinyl-composite plank that is more water-resistant, which is why it's popular in Australian kitchens and laundries. Both are sold by the box, so the calculation is identical — just use each product's box coverage.
Is GST included in the estimate?
Only if you include it. Advertised Australian retail prices normally already include 10% GST, so enter the shelf price with tax at 0 — or an ex-GST trade price with 10% tax and the calculator adds it.
Keep planning
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About this calculator
- Written by:
- BuildMeasure Editorial Team
- Technically reviewed by:
- Pending independent technical reviewer (formula unit-tested; see methodology)
- Last reviewed:
- 2026-07-16
- Formula version:
- 1.0.0
- Region reviewed for:
- Australia
- Spotted an error?
- Report a correction
Methodology
- Room area comes either from length × width or from a directly entered area. All arithmetic runs internally in SI units (m²); regional units (feet, ft²) are converted exactly on the way in and out.
- The area to purchase = room area × (1 + wastage %). Wastage covers end-of-row cuts, defects and spares, and depends mainly on the laying pattern — the default 8% suits a straight plank lay.
- When you enter the coverage per box from the box label, boxes = purchase area ÷ box coverage, rounded UP to a whole box, because flooring is sold in sealed boxes.
- The cost estimate uses the price you enter: price per box × boxes when a box price is given (it takes precedence), otherwise price per area × the purchase area; the tax rate you enter is then applied. No prices are built in.
- The formula is covered by automated unit tests, including hand-calculated worked examples, and is versioned (see formula version on this page).
Sources & standards
- Unit definitions: Metric units throughout; areas in m².
- Wastage allowances: 8% straight lay / 15%+ herringbone are standard planning allowances; confirm with your installer.
This tool provides a material estimate for planning purposes only. It is not a quotation, and it does not cover underlay, trims, subfloor preparation or installation. Confirm quantities and box coverage with your flooring supplier before ordering.