Flooring Calculator
Find how much flooring you need for a room and how many boxes to buy. Enter each room's shape and size, choose the layout, and enter the coverage printed on the box. It works for laminate, vinyl plank, and hardwood. For tile, use the Tile Calculator. For carpet cut from a roll, use the Carpet Calculator.
Add rooms, closets, or hallways, or subtract areas that need no flooring, such as a kitchen island.
- Choose US or Metric. You can still change the unit of any single field.
- Pick the shape of the room and enter its dimensions. Use Add section for closets, hallways, or other rooms that get the same flooring. Set a section to Subtract for areas that need no flooring, such as a kitchen island or a fireplace hearth.
- Choose the Layout. It sets the waste allowance: 10% for a straight layout and 15% for diagonal or herringbone. You can change the allowance, and Reset brings back the recommended value.
- Enter the Coverage per box printed on the box or the product page, in square feet or square meters, to see how many boxes to buy.
- Optionally, enter a price per square foot, square yard, square meter, or box to estimate the cost.
An L-shaped room is two rectangles added together, or a large rectangle
with the missing corner subtracted. Dimension fields accept whole numbers,
decimals, fractions, and mixed numbers, such as 12,
10.5, 3/4, or 30 1/2. Choose
ft + in as the unit to enter a length such as 12 ft 6 in
in two fields.
How much flooring you need
The area of a rectangular room is:
Area = length × width
For other shapes, the calculator uses these formulas. With several sections, it adds the sections set to Add and subtracts those set to Subtract.
| Shape | Area |
|---|---|
| Rectangle | length × width |
| Circle | π × diameter² ÷ 4 (or π × radius²) |
| Triangle (base and height) | base × height ÷ 2 |
| Triangle (three sides) | Heron's formula: √(s(s − a)(s − b)(s − c)), where s = (a + b + c) ÷ 2 |
| Trapezoid | (parallel side A + parallel side B) ÷ 2 × height |
| Ring | π × (outer diameter² − inner diameter²) ÷ 4 |
| Rectangular border | outer length × outer width − (outer length − 2 × border width) × (outer width − 2 × border width) |
| Known area | the area you enter |
Then it adds the waste allowance and divides by the coverage per box:
Total area = net area × (1 + waste % ÷ 100)
Boxes = total area ÷ coverage per box, rounded up
Convert the area and the coverage to the same unit before you divide. One square yard is 9 ft², and one square foot is 0.09290304 m².
How much extra flooring to buy
Cutting planks to fit the walls leaves offcuts, and layouts at an angle leave more. The calculator starts from these allowances:
| Layout | Waste allowance |
|---|---|
| Straight Planks parallel to a wall, including staggered and random-length layouts | 10% |
| Diagonal Planks at 45° to the walls | 15% |
| Herringbone or chevron Short planks meeting at an angle in a zigzag pattern | 15% |
- Pergo's Installation Essentials Guide says to add 10% to the square footage for standard installations and 15% for diagonal installations.
- The flooring supplier Havwoods recommends 10% for plank flooring and 15% for herringbone and chevron in areas under 100 m², and 7% and 12% for larger areas.
- Shaw's installation instructions for solid hardwood call for 5 to 10%, depending on the layout, and more for diagonal, herringbone, or bordered installations.
Small rooms, rooms with many corners, and angled layouts need a larger allowance than large, simple rooms. Follow the manufacturer's instructions for your flooring, and change the waste allowance to match.
How much a box of flooring covers
The coverage per box depends on the size and number of planks, so it varies between products, even from the same brand. Some examples:
| Product | Coverage per box |
|---|---|
| Lifeproof luxury vinyl plank (US) | 20.1 sq ft |
| Pergo Outlast+ laminate (US) | 19.63 sq ft |
| Bruce solid hardwood, 3/4 in × 2-1/4 in (US) | 20 sq ft |
| Quick-Step laminate (UK) | 1.596 to 2.048 m² |
These are only examples. Check the coverage printed on the box or the product page of the flooring you buy.
Examples
A rectangular room
A room 12 ft × 10 ft is 120 ft². With a 10% waste allowance for a straight layout, the total is 132 ft² (14.67 yd², or 12.26 m²). With boxes of 20.1 sq ft, that is 132 ÷ 20.1 = 6.57, so buy 7 boxes. At $60 per box, the cost is $420.00.
The same room laid diagonally
With boxes of 19.63 sq ft, a straight layout needs 132 ÷ 19.63 = 6.72, or 7 boxes. Laid diagonally with a 15% allowance, the total is 138 ft², and 138 ÷ 19.63 = 7.03, so buy 8 boxes.
An L-shaped room
Split the room into a 12 ft × 10 ft rectangle and an 8 ft × 6 ft rectangle: 120 + 48 = 168 ft². With 10% added, the total is 184.8 ft². With boxes of 20 sq ft, that is 9.24, so buy 10 boxes.
Metric dimensions
A room 4 m × 3.5 m is 14 m². With 10% added, the total is 15.4 m². With packs of 1.824 m², that is 8.44, so buy 9 packs. At £25 per square meter, the cost is £385.00.
FAQ
It depends on the product. Many laminate, vinyl plank, and hardwood boxes in the US cover about 20 sq ft, and many laminate packs in the UK cover about 2 m². Use the coverage printed on your box.
About 10% for a straight layout and 15% for a diagonal or herringbone layout. Add more for small rooms or rooms with many corners.
With a 10% allowance, you need 1,100 ft² of flooring. With boxes of 20.1 sq ft, that is 54.73, so buy 55 boxes.
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