Flooring Calculator
How many boxes of laminate, vinyl plank or hardwood to buy, plus underlayment and baseboard.
Boxes to buy
10
boxes
180 sq ft of floor plus 10% extra is 198 sq ft to buy.
Flooring
- Area to buy, with extra
- 198 sq ft
- Area in those boxes
- 200 sq ft
- Floor area
- 180 sq ft
Underlayment and trim
- Underlayment, 100 sq ft rolls
- 2 rolls
- Baseboard or quarter-round
- 51 ft
Cost
- Flooring (boxes bought)
- –
How much flooring do I need?
Multiply the room's length × width for its square footage, add about 10% for cuts, then divide by the square feet in one box and round up. A 15 × 12 ft room is 180 sq ft; with 10% extra that's 198 sq ft, or 10 boxes of 20 sq ft.
Worked example: a 15 × 12 ft living room
- Area: 15 × 12 = 180 sq ft.
- Extra: +10% for cuts and the ends of rows = 198 sq ft.
- Boxes: 198 ÷ 20 sq ft per box = 9.9, so 10 boxes (200 sq ft).
- Underlayment: 180 sq ft = 2 rolls of 100 sq ft (if your flooring doesn't have it attached).
- Baseboard: perimeter 54 ft minus a 3 ft doorway = 51 ft.
Boxes for common rooms
With 10% extra and boxes of 20 sq ft. Your box size will differ, so enter it in the calculator.
| Room | Floor area | With 10% extra | Boxes (20 sq ft) |
|---|---|---|---|
| 10 × 10 ft | 100 sq ft | 110 sq ft | 6 |
| 12 × 12 ft | 144 sq ft | 158.4 sq ft | 8 |
| 15 × 12 ft | 180 sq ft | 198 sq ft | 10 |
| 20 × 15 ft | 300 sq ft | 330 sq ft | 17 |
How much extra to buy
- About 10% for a straight, side-to-side layout in a simple room.
- 15% or more for diagonal or herringbone patterns, or rooms with lots of corners, closets and doorways.
- Keep a box spare for future repairs. Later batches can differ in color.
Before you buy
- Use the box's coverage, not a guess. Boxes of the same type of flooring can hold very different amounts.
- Check the lot number on every box so the color matches.
- Underlayment: many vinyl and laminate planks have it attached. If yours does, you may not need more; check the maker's guidance.
- Let it acclimate: many makers ask you to leave the boxes in the room for a day or two before installing.
Frequently asked questions
How many boxes of flooring do I need for a 12 × 12 room?
144 sq ft plus 10% is 158.4 sq ft. With 20 sq ft boxes that's 8 boxes; divide by your box's coverage for your product.
How much extra flooring should I buy?
About 10% for a straight layout and 15% or more for diagonal patterns or rooms with many corners.
How do I measure a room for flooring?
Measure the length and width wall to wall, in feet, and multiply. For an L-shaped room, split it into rectangles and add them; the square footage calculator handles L-shapes.
How much baseboard do I need?
Add up the room's perimeter and subtract the width of each doorway. A 15 × 12 ft room with one doorway needs about 51 ft.
Related calculators
Square Footage CalculatorSquare feet of any room or area, in sq ft, sq yd, m² and acres.Tile CalculatorHow many tiles and boxes for a floor, wall or backsplash, grout joints included.Drywall CalculatorDrywall sheets, screws, tape and joint compound for a room, with cost.Paint CalculatorGallons of paint for a room's walls and ceiling, with doors, windows and coats.
Sources and method
- Box coverage and installation guidance: your flooring maker's product page and instructions — area units per NIST Handbook 44
Last checked October 12, 2026. How we build and test every calculator: methodology.