How Much Flooring Do I Need? Boxes, Waste and Getting It Right

Published 2026 · 4 min read

Flooring is sold in boxes, each covering a certain square footage. The number to remember: your room's area, plus a waste allowance for cuts and mistakes.

The calculation

Measure the room's length and width, multiply for square feet. Multiply by 1.10 (a 10% waste allowance) and divide by the square feet per box. Round up — you can't buy a fraction of a box.

How much waste is realistic?

• Straight lay in a rectangular room: 5?10%.
• Diagonal or herringbone: 10?15%.
• Irregular rooms, lots of doorways: 15%+.

Why the allowance matters

You'll cut planks to fit walls, doorways and pipes. Planks also come in batches — mixing dye lots across rooms looks bad, and getting more later is a gamble. Order enough the first time.

Run the numbers

Use the flooring calculator — enter the room size, waste allowance and box coverage, and it returns the exact boxes to buy.

If you are installing over a subfloor, add underlayment or padding to your material list - it is not counted in the square footage but is required under most floating floors. And always buy from a single order: two deliveries weeks apart can come from different dye lots, and a visible shade line in a doorway is a mistake no installer can fix.

Finally, round every result up to whole boxes and check the box coverage on the specific product you are buying - coverage ranges from about 15 to 30 square feet per box depending on plank width and thickness. Under-buying by even half a box means a second order, a possible dye-lot mismatch and a delayed install.