Flooring calculator
Pick your flooring, enter the room size and, for plank floors, the square feet in a box. You get the area to buy with the waste allowance, the number of boxes and, if you add a price, the cost. Choose carpet and it works out the order from a roll instead, so it doubles as a carpet calculator. The defaults are a 14 × 20 ft room in hardwood.
How the calculator works
- Area = length × width for one room, or the rooms added up, minus anything you won't floor.
- Buy area = area × (1 + waste %). The extra covers cutting, boards you reject and mistakes. Which percentage is the next section.
- Boxes = buy area ÷ square feet per box, rounded up. You can't buy half a box, so the spare you actually end up with is shown too.
- Cost (optional) = whole boxes × price per box, or whole boxes × coverage × price per square foot. It's flooring only: underlayment, trim, transitions, removal and labor are extra. For installed prices, see hardwood floor installation cost and carpet installation cost.
Waste allowances: what is published and what is our default
| Flooring and layout | Allowance | Basis |
|---|---|---|
| Hardwood, straight | 5% | Bruce: for cutting and grading |
| Hardwood, diagonal | 10% | Bruce |
| Laminate, straight | 10% | Pergo installation guide |
| Laminate, diagonal | 15% | Pergo installation guide |
| Vinyl plank or other click-lock | 10% straight, 15% diagonal | Our default, same as laminate; no single standard |
| Herringbone or other pattern | 20% | Our default, not a standard |
Only the Bruce and Pergo rows are manufacturer figures, and they apply to those brands' products. The calculator says on every result which kind of figure it used. Other makers can ask for more or less, and a small room with many cuts, doorways and closets can need more. If your carton or installer gives a different number, type it into the waste box and it replaces the preset.
Carpet: how the roll order is worked out
Wall-to-wall carpet is cut from a roll, usually 12, 13.5 or 15 ft wide, so a room is covered with strips. The calculator tries the strips running along each direction of every room. It allows 3 inches of extra carpet at each wall for trimming, which is the allowance in the Carpet and Rug Institute's installation standard (CRI 105). It then picks the layout that uses the least carpet. A room wider than the roll needs a seam. Each room is cut separately and the lengths are added up, so it's an order estimate, not a seam plan: your installer may lay out differently, for example to hide a seam or match pattern. Carpet is also sold by the square yard, which is 9 square feet.
Worked examples
- Hardwood, 14 × 20 ft, straight, 20 ft² boxes. Area 280 ft². With 5%: 280 × 1.05 = 294 ft². 294 ÷ 20 = 14.7, so 15 boxes (300 ft²), leaving 20 ft² spare. Laid diagonally with 10%: 308 ft², 16 boxes.
- Laminate, same room, straight. 280 × 1.10 = 308 ft², 16 boxes of 20 ft² (320 ft², 40 ft² spare).
- Carpet, 14 × 11 ft on a 12 ft roll. The 11 ft width plus trim (11.5 ft) fits in one strip, and the 14 ft length plus trim is 14.5 ft. 14.5 × 12 = 174 ft², or 19.3 yd², for a 154 ft² room: no seams, and about 13% over the floor area.
Assumptions and things that change the answer
- Check the carton. Coverage per box varies by product. Use the figure printed on the box and buy every box from the same lot where you can, because shade and size can vary between production runs.
- Measure the room as it is. Closets, alcoves and doorway thresholds count. For several rooms, add them in the "Several rooms" mode, or use the square footage calculator for L-shaped and irregular rooms and enter the total as a known area.
- Hard floors are different. For ceramic and porcelain tile, with tiles per box and grout, use the tile calculator.
- Pricing. The cost box is for your own prices. This page publishes none. For published installed ranges, see hardwood floor installation cost.
Wear eye protection and gloves when cutting planks and handling edges, and use a dust mask when you saw. Carpet rolls and boxes of plank flooring are heavy, so lift with a helper. Tack strip nails point up. If you are pulling up old resilient flooring, don't sand or scrape it until you know what it is, as older products can contain asbestos (US EPA).
Pricing the job? See hardwood floor installation cost and carpet installation cost. For tile, try the tile calculator.
Sources
- Bruce, hardwood installation instructions and hardwood flooring FAQs: 5% for cutting and grading, 10% for diagonal installation.
- Pergo, Installation Essentials Guide (PDF): 10% for a standard installation, 15% for diagonal.
- The Carpet and Rug Institute, CRI 105 Standard for installation of residential carpet (2015, PDF): 3 in trim allowance at each wall.
- US EPA, Protect your family from exposures to asbestos.