Flooring Calculator
Calculate boxes of laminate, vinyl plank or hardwood flooring for any room, with layout waste, underlay and baseboard length.
- Free
- No sign-up
- Formula shown
- US & metric
Your estimate
Boxes needed (incl. 7% waste)
9 boxes
- Floor area
- 168 sq ft
- Area to buy
- 179.8 sq ft
- Coverage purchased
- 180 sq ft
Show the math
- Area = L × W (+ extra L × W) = 168 sq ft
- × (1 + 7%) = 179.8 sq ft
- ÷ 20 sq ft per box → 9 boxes (rounded up)
Shopping list & cost
| Item | Spec | Qty | Cost |
|---|---|---|---|
| Flooring | 20 sq ft per box | 9 boxes | — |
| Underlayment | roll / sheet | 176.4 sq ft | — |
| Baseboard / quarter-round | minus door openings | ≈ 52 ft | — |
Prices are what you enter under Advanced options. Estimates only — check stock and pricing with your supplier.
Quick answer A 14 × 12 ft room (168 sq ft) laid straight with 7% waste needs 9 boxes of flooring at 20 sq ft per box. A 4.5 × 3.6 m room needs 8 boxes at 2.2 m² per pack. Diagonal layouts need about 12% extra and herringbone about 15%. Boxes are always rounded up.
Diagram
How to use this calculator
- Measure the room wall to wall at the widest points.
- For L-shaped rooms, add the second rectangle under Advanced options.
- Choose the layout; diagonal and herringbone create more offcuts.
- Enter the coverage per box exactly as printed on the carton.
- Use the underlay and baseboard lines in the shopping list as a starting point.
Method & assumptions
Area = Length × Width (+ extra rectangles) Boxes = Area × (1 + waste %) ÷ coverage per box, rounded up
- Coverage per box
- sq ft or m² printed on the carton
- Waste %
- offcuts and defects; depends on layout
Assumptions & limits
- Area includes closets and doorways you plan to floor.
- Baseboard length is the room perimeter — subtract door widths yourself.
- Underlay is estimated at area + 5% overlap.
Rounding: purchase quantities are always rounded up to whole bags, boxes, sheets or bundles. See our methodology.
Worked examples
Imperial: living room 18 × 15 ft, LVP at 23.6 sq ft/box
- Area = 270 sq ft; +7% = 288.9 sq ft
- 288.9 ÷ 23.6 = 12.2 → 13 boxes
Metric: hallway 5 × 1.2 m herringbone, 1.3 m²/pack
- Area = 6 m²; +15% = 6.9 m²
- 6.9 ÷ 1.3 = 5.3 → 6 packs
In depth: flooring planning notes
Measuring rooms that are not rectangles
Most rooms are not perfect rectangles. The easiest way to measure an L-shaped or T-shaped room is to split it into rectangles, measure each and add the areas. Include closets and alcoves that will be floored, and measure into door openings to the middle of the threshold. Measure at floor level, not along a skirting board that may be out of line, and round each measurement up to the nearest inch or centimeter.
Our flooring calculator handles a single rectangle; for complex rooms, use the square-footage calculator for each part and enter the total area. Write the numbers down on a sketch — you will need them again for underlay and trim.
Waste, acclimation and buying the right number of boxes
Laminate and vinyl plank come in boxes with coverage printed on the end, for example 19.8 sq ft or 2.22 m². Divide the floor area plus waste by that figure and round up. Straight installations in a simple room usually need 5–7% extra; rooms with many corners, door frames and pipes need 10%, and diagonal or herringbone layouts 15% or more. Engineered and solid hardwood vary more board-to-board, so allow extra to cull defects.
Many floors must acclimate in the room before installation — often 24–48 hours with the boxes flat and opened at the ends. Check the manufacturer's guidance, and leave the expansion gap they specify at every wall; skirting or quarter-round covers it.
Underlay is sold in rolls by area, and skirting or baseboard by length. The calculator estimates skirting from the room perimeter minus door openings, so you can order it at the same time. Keep one unopened box after the job: matching a discontinued floor later is very hard.
Subfloor preparation and extras
The subfloor must be flat, clean and dry before any floating floor goes down. Many manufacturers specify a maximum deviation, such as about 3/16 in over 10 ft (or 3–5 mm over 2 m). Self-levelling compound fills hollows on concrete; high spots are ground or sanded. Concrete slabs usually need a vapour barrier unless the underlay includes one.
Plan the extras at the same time as the boxes: underlay rolls, transition strips at doorways, stair nosings, door-frame undercut tools and spacers for the expansion gap. Ordering everything together avoids a second trip that stalls the job halfway through a room.
Reference table
| Layout | Extra |
|---|---|
| Straight, rectangular room | 5–7% |
| Many corners / closets | 10% |
| Diagonal | 10–15% |
| Herringbone / chevron | 15%+ |
Key facts
- 1 m²
- 10.764 sq ft
- Acclimate wood/laminate
- typically 48 h (check manufacturer)
- Expansion gap
- per manufacturer, often ~1/4–3/8 in (6–10 mm)
Tips & common mistakes
- Open boxes from several cartons and mix planks to avoid patches of one shade.
- Keep one spare box for future repairs.
- Remember the expansion gap at walls — it is hidden by the baseboard.
Frequently asked questions
How much flooring do I need for a 12×12 room?
144 sq ft plus 7% waste = 154 sq ft; with 20 sq ft boxes that is 8 boxes.
How much extra flooring should I buy?
5–10% for straight installs, 10–15% for diagonal and around 15% for herringbone.
Do I include closets?
Yes, if you are flooring them. Measure them as extra rectangles.
How much underlayment do I need?
About the floor area plus 5% for overlaps (if your underlay overlaps); some flooring has it pre-attached.
How do I calculate baseboard?
Baseboard ≈ room perimeter minus door openings. Buy 10% extra for mitred corners.
Sources
- National Wood Flooring Association – installation guidelines — checked 2026-10; verify before launch
- Pergo – installation instructions — checked 2026-10; verify before launch
- NIST – unit conversion factors — checked 2026-10; verify before launch
Default values (bag yields, coverage rates, densities) are typical figures from manufacturer literature. Always check the label on the product you buy.
Related calculators
- Tile CalculatorCount floor or wall tiles and boxes, with grout joints and extra for straight, offset, diagonal or herringbone layouts.
- Square Footage CalculatorFind the area of a room or yard in square feet, square meters and square yards — rectangles, triangles, circles and trapezoids.
- Paint CalculatorWork out gallons or liters of paint for a room, with doors, windows, coats, ceiling and primer — plus the tin sizes to buy.
Learn more in our guides
Cite or embed this calculator
DIYCalcLab. “Flooring Calculator.” Oct 18, 2026. https://diycalclab.com/flooring/flooring-calculator/
An embeddable version for blogs and contractor sites is planned.
Estimates only. Verify quantities with your supplier and local building codes. For structural, electrical or safety-critical work, consult a licensed professional. Full disclaimer.