How to calculate flooring
Measure the room’s length and width in feet and multiply them to get the area. Add a waste allowance, then divide by the coverage of one box.
Flooring to buy = length × width × (1 + waste %)
Boxes = flooring to buy ÷ square feet per box, rounded up
Worked example
A room 14 feet by 16 feet is 224 square feet. With 10% waste you need 246.4 square feet. If each box covers 22 square feet, 246.4 ÷ 22 = 11.2, so buy 12 boxes.
Waste allowance by material and layout
| Flooring | Typical waste |
|---|---|
| Laminate or vinyl plank, straight | 5% to 10% |
| Hardwood, straight | 10% |
| Any plank, diagonal | 15% |
| Herringbone or chevron | 15% to 20% |
| Tile | 10% to 15% |
Rooms that are not rectangles
Split the room into rectangles, calculate each and add them together. Include closets. Do not subtract small areas such as floor vents.
How to use this calculator
Enter the length and width of the room, a waste allowance and the coverage per box printed on the box. The flooring calculator returns the room area, the square feet to buy and the number of boxes. Add a price per square foot to see the material cost. If a measurement includes inches, turn them into a decimal by dividing by 12, so 13 feet 6 inches becomes 13.5 feet.
What the result means
You get two numbers. The square feet to buy is the room area plus waste. The box count is that figure rounded up to whole boxes, and it is the one that sets your cost, because stores do not sell part of a box.
In the worked example, 12 boxes at 22 square feet each is 264 square feet, not 246.4. If the flooring costs $4 per square foot, for example, the material comes to 264 × $4 = $1,056.
More examples
An L-shaped room with a closet
Split the room into a 12 by 15 foot rectangle (180 square feet) and a 6 by 8 foot rectangle (48 square feet). Add a 2 by 6 foot closet (12 square feet). The total is 240 square feet. With 10% waste you need 264 square feet. If each box covers 20 square feet, 264 ÷ 20 = 13.2, so buy 14 boxes.
A room measured in feet and inches
A room 13 feet 6 inches by 11 feet 3 inches is 13.5 × 11.25 = about 151.9 square feet.
The same room at different waste allowances
This table uses the 224 square foot room and 22 square foot boxes from the worked example.
| Waste | Flooring to buy | Boxes |
|---|---|---|
| 5% | 235.2 sq ft | 11 |
| 10% | 246.4 sq ft | 12 |
| 15% | 257.6 sq ft | 12 |
| 20% | 268.8 sq ft | 13 |
Because boxes are rounded up, a higher waste allowance does not always mean another box.
What changes the result
- Room area. This is the largest factor. Measure each wall rather than trusting a listing or a plan.
- Layout. Diagonal and herringbone patterns need more cuts, so they need a higher waste allowance.
- Box size. Coverage per box differs between products. Check the label of the exact flooring you are buying.
- Room shape. Alcoves, angles and doorways mean more cut boards.
Common mistakes
- Leaving out closets, hallways and the floor inside doorways.
- Rounding the box count down.
- Multiplying feet and inches without converting, such as treating 13 feet 6 inches as 13.6 feet.
- Pricing the job on the room area instead of the full boxes you have to buy.
- Budgeting for the flooring alone. Underlayment, transition strips and baseboard or trim are separate items.
Related calculators
For rooms with an awkward shape, add up the area with the square footage calculator first. The tile calculator counts individual tiles by size, and square feet to linear feet helps when boards are sold by length rather than by the box. For the whole project budget, see the renovation cost calculator.
Frequently asked questions
How much flooring do I need for a 12 by 12 room?
144 square feet, or about 158 square feet with 10% waste.
Is carpet measured the same way?
Carpet is often priced by the square yard. Divide square feet by 9, or use the square yard calculator.
Should I buy extra boxes?
Keeping one spare box helps with later repairs, since colors can differ between production runs.
How many boxes of flooring do I need for 200 square feet?
With 10% waste you need 220 square feet. If each box covers 20 square feet, that is 11 boxes. Divide by the coverage on your own box, since it varies by product.
How do I measure a room in feet and inches?
Divide the inches by 12 and add the result to the feet. 10 feet 9 inches is 10.75 feet.
Do I include the floor under cabinets and appliances?
Include the floor under appliances that move, such as a refrigerator or range. For fixed cabinets it depends on whether the flooring will run underneath them, so decide that before you measure.
Does the layout pattern change how much flooring I need?
Yes. The room area is the same, but angled patterns produce more offcuts. Use the higher waste figures in the table above for diagonal, herringbone and chevron layouts.