Flooring Calculator
Work out how many boxes of flooring you need for a room or several rooms. Enter the measurements, the coverage printed on the box, and an allowance for cuts and waste.
How to use the calculator
- Measure the length and width of each room or area. Use Add another area for more than one.
- Enter the coverage per box. It is printed on the box or in the product details. The value shown is an example.
- Choose a waste allowance. See the guide below for common figures by flooring type and layout.
- Add a price per box or per square foot if you want a cost estimate.
How the calculation works
- Floor area = length × width, added up for every area.
- With waste = area × (1 + waste percent ÷ 100).
- Boxes = area with waste ÷ coverage per box, rounded up to a whole box.
- Flooring you will buy = boxes × coverage per box.
- Leftover = flooring you will buy − the floor area.
How much waste to allow
Flooring guides give these ranges. They vary between sources, so treat them as starting points and ask your installer or supplier for the figure they use.
| Flooring | Straight layout | Diagonal, herringbone or chevron |
|---|---|---|
| Laminate | about 5 to 8% | about 12 to 14% |
| Luxury vinyl plank or tile | about 7 to 10% | about 10 to 12% |
| Engineered hardwood | about 7 to 10% | about 12 to 15% |
| Solid hardwood | about 10% | about 15 to 17% |
| Large-format tile (12 inches or more) | about 10% | about 15% |
| Natural stone tile | about 15 to 20% | toward the high end of that range |
Angled layouts waste more because the cuts at the walls cannot be reused as neatly. Rooms with lots of corners, alcoves or doorways also waste more than a plain rectangle. See the guide on how much extra flooring to buy for more.
Worked example
A living room 12 ft by 15 ft and a hallway 4 ft by 6 ft, with a 10 percent allowance, boxes of 20 square feet, and a price of $3.50 per square foot. These are example figures.
- Area: 12 × 15 + 4 × 6 = 204 sq ft
- With 10 percent extra: 224.4 sq ft
- Boxes: 224.4 ÷ 20 = 11.22, so buy 12
- Flooring bought: 12 × 20 = 240 sq ft, which leaves 36 sq ft over
- Cost: 240 sq ft × $3.50 = $840, which is $70 a box
Questions
How many boxes of flooring do I need?
Work out the floor area, add an allowance for cuts and waste, divide by the coverage printed on one box, and round up to whole boxes. The calculator does all of that. Always check the coverage on the box you are actually buying, because it varies between products.
Why does the calculator round up to whole boxes?
Flooring is sold in full boxes, so you cannot buy part of one. Rounding up also means the leftover is shown, which is useful when you are deciding whether a box is worth it for a small shortfall.
Should I buy extra for future repairs?
Many installers suggest keeping a few spare planks or tiles, because the same product may not be available later and different batches can vary slightly in color. The leftover from a rounded-up order often covers this. It is worth asking your supplier whether to buy everything in one go from the same batch.
Do I include closets and hallways?
Yes, if the flooring will run into them. Measure each area and use Add another area for each one. Floor under permanent cabinets is usually left uncovered, so you can leave it out.
Does this work for tile and vinyl as well as wood?
Yes. The calculation is the same for any flooring sold by coverage per box. The waste allowance is what changes between them, and the guide below shows common figures.
What if my rooms are not rectangles?
Split the room into rectangles and use Add another area for each. If you already know the area, choose I know the area. A circle is also available if you have a round space.