How to calculate flooring
boxes = room area × (1 + waste %) ÷ coverage per box
Measure the room at its widest points, multiply length by width, add your waste allowance and divide by the coverage printed on the box. Always round up: stores sell whole boxes.
Worked example
A 15 × 12 ft living room is 180 sq ft. With 10 percent waste you need 198 sq ft. At 20 sq ft per box, that is 9.9, so buy 10 boxes.
Measuring rooms that are not rectangles
Split L-shaped and irregular rooms into rectangles, work out each one and add them together. Include closets and the floor under appliances you are moving. For a bay window or angled wall, measure to the furthest point; the small extra goes into your waste margin.
How much waste to allow
| Room and layout | Waste |
|---|---|
| Simple rectangle, click vinyl plank | 5 to 7% |
| Most rooms, laminate or hardwood | 10% |
| Diagonal layout, many corners or closets | 15% |
Before installing
- Leave laminate and wood flooring in the room to acclimate for as long as the manufacturer says, often about 48 hours.
- Floating floors need an expansion gap at the walls, usually about 1/4 inch (6 mm). Follow the installation sheet.
- Use the perimeter result to buy baseboard, skirting or quarter-round. Subtract the width of door openings.
- Check whether your product needs a separate underlayment. Some vinyl planks come with one attached.
Frequently asked questions
How many boxes of flooring do I need for a 12 × 12 room?
A 12 × 12 room is 144 sq ft. Add 10 percent and you need about 158 sq ft. At 20 sq ft per box, buy 8 boxes.
How do I convert square feet to square yards for carpet?
Divide square feet by 9. A 12 × 15 ft room is 180 sq ft, or 20 square yards.
Should I buy an extra box?
Many installers keep one spare box for future repairs, because the same colour and batch can be hard to find later.
Does this work in square metres?
Yes. Switch to metric at the top of the page and enter the room in metres and the box coverage in m².
Last updated November 1, 2026.