Laminate, luxury vinyl plank (LVP), engineered wood and solid hardwood are all sold in boxes labelled with the square feet they cover. This flooring calculator measures the room, adds a waste allowance suited to your layout and divides by the coverage per box, so you buy whole boxes with a sensible margin. It also counts underlayment rolls and estimates the cost at your price per square foot.
Waste is the number that varies most. Flooring installed in straight rows parallel to a wall wastes the least; diagonal and herringbone patterns waste far more because every row ends in an angled cut. For ceramic or porcelain tile, use the tile calculator, which counts individual tiles. For L-shaped or multi-room layouts, total the areas first with the square footage calculator.
How to use the flooring calculator
- Measure the room at its longest and widest points, including closets and under appliances that will get the floor. For irregular rooms, add up rectangles and enter the total as length × 1.
- Choose a waste allowance: 5–10% for a straight lay in a simple room, around 15% for diagonal, and 15–20% for herringbone or rooms with many angles.
- Enter the square feet per box from the product label or spec sheet. Coverage varies widely by plank size and brand.
- Enter your underlayment roll coverage if the floor needs separate underlayment (many LVP and some laminate products have it pre-attached).
- Add a price per square foot to estimate the cost of the boxes you will actually buy.
Formula
Cost uses the square footage you actually buy (whole boxes), not just the room area. 1 ft² = 0.0929 m².
Worked example
A 15 × 12 ft living room, laminate laid straight with 10% waste, 24 ft² per box, 100 ft² underlayment rolls, at an illustrative $2.49 per ft².
- Area: 15 × 12 = 180 ft² (16.72 m²).
- With waste: 180 × 1.10 = 198 ft².
- Boxes: 198 ÷ 24 = 8.25, so 9 boxes = 216 ft² (18 ft² spare).
- Underlayment: 180 ÷ 100 = 1.8, so 2 rolls.
- Cost: 9 × 24 × $2.49 = $537.84.
Acclimation, expansion gaps and spare boxes
Wood and many laminate products must acclimate to the room before installation, and floating floors need an expansion gap at the walls that is hidden by baseboard or quarter-round. The National Wood Flooring Association publishes installation guidelines for wood floors, including moisture testing and acclimation; laminate and vinyl manufacturers specify their own gap sizes and acclimation times. Follow the instructions for your product, since warranties often depend on it.
Keep at least one unopened box after the job. Flooring lines are discontinued and dye lots vary, so a spare box is the easiest way to repair a damaged plank years later.
Waste allowance by layout
| Layout | Typical waste allowance |
|---|---|
| Straight lay, simple rectangular room | 5–10% |
| Rooms with closets, alcoves or many doorways | 10–15% |
| Diagonal (45°) | About 15% |
| Herringbone or chevron | 15–20% |
These are common installer allowances rather than fixed rules; check your product's installation guide, which may recommend a specific figure.
Caveats and assumptions
- Coverage per box varies by product. Always use the figure on the box or the spec sheet.
- Stairs, landings and transitions need special pieces (stair nose, reducers, T-moldings) sold separately by the piece.
- Concrete subfloors may need a vapor barrier; follow the manufacturer's requirements.
- Prices in examples are illustrative, not quotes.
Frequently asked questions
How many boxes of flooring do I need?
Multiply length × width, add your waste allowance and divide by the square feet per box, rounding up. A 180 ft² room with 10% waste and 24 ft² boxes needs 9 boxes.
How much extra flooring should I buy?
About 10% for a straight installation in a typical room, and 15–20% for diagonal or herringbone patterns.
Do I need underlayment for vinyl plank?
Many LVP products have underlayment attached, and adding a second layer can void the warranty. Laminate usually needs a separate underlayment unless it has a pad attached. Check the product instructions.
How do I measure an L-shaped room?
Split it into two rectangles, multiply length × width for each and add them. The square footage calculator does this for any number of sections.
How many square feet are in a box of laminate?
It varies by plank size and thickness; many boxes hold roughly 15–30 ft². Use the exact figure printed on the box.
Sources
- National Wood Flooring Association — Installation guidelines — acclimation, moisture testing and installation of wood floors
- NIST — Unit Conversion — ft² to m²
This calculator gives estimates for planning and education. Check measurements, local codes, supplier specs and your school's official policy before relying on a result. See our disclaimer and how we build and check calculators.