Flooring & Tile
Flooring Calculator
Enter your room dimensions in metres to get the square metres of flooring to buy and the number of packs, 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 5 m × 4 m room is 20 m². For L-shaped rooms, add the rectangles and use direct-area mode.
A wastage allowance is added on top (default 8% for a straight lay; 15% or more for herringbone), then the total is divided by the coverage printed on the pack — commonly around 2–2.5 m² for laminate or luxury vinyl — and rounded up to whole packs, because flooring is sold in sealed packs.
Real-world example
Worked example: 5 m × 4 m living room, laminate, 8% wastage
- Room area: 5 × 4 = 20 m².
- Add 8% wastage: 20 × 1.08 = 21.6 m² to purchase.
- Packs at 2.2 m² per pack: 21.6 ÷ 2.2 = 9.82.
- Round up to whole packs: 10 packs.
Buy 10 packs (22 m²). At an example price of £25 per pack plus 20% VAT, that's £250.00 + £50.00 = £300.00.
Before you start
How to measure
- Measure the room in metres wall to wall, ignoring skirting boards — laminate runs under or up to the skirting depending on whether you refit it or add beading.
- Take the m² coverage per pack from the pack label; it varies by board size and brand, so 2.2 m² is only a typical figure.
- Include alcoves, bay windows and doorway thresholds; split irregular rooms into rectangles and add the areas in direct-area mode.
Local guidance
Notes for United Kingdom
- UK laminate and luxury vinyl are priced per m² but sold in packs; the pack label states the m² coverage and board dimensions.
- Skirting boards matter to the estimate: removing and refitting them lets flooring run to the wall, while scotia beading covers the expansion gap if they stay in place — neither is included here.
- VAT at the standard 20% rate applies; retail prices normally include it, online trade prices sometimes don't — 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 / parquet-style | 15–20% |
Planning values only — your fitter 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 damaged boards happen.
- Ignoring the expansion gap requirement around the perimeter when measuring tightly.
- Comparing per-m² and per-pack prices without converting via the pack coverage.
- Using the straight-lay allowance for herringbone LVT, which consumes far more in angled cuts.
Need help?
Frequently asked questions
How many packs do I need for a 20 m² room in herringbone?
Use a 15% allowance: 20 × 1.15 = 23 m². At 2.2 m² per pack, 23 ÷ 2.2 = 10.45, so buy 11 packs — herringbone's angled cuts are why it needs more than the straight-lay 8%.
Do I need underlay as well?
Usually yes for laminate (unless it's pre-attached), sold separately by the roll in m². The purchase area from this calculator is also the underlay area you need.
Is VAT included in the estimate?
Only if you include it. Enter the shelf price with tax at 0 if VAT is already in it, or an ex-VAT trade price with 20% and the calculator adds it.
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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:
- United Kingdom
- 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 fitter.
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.