Measure every room and closet as rectangles, add them up, then add extra for cuts. The calculator rounds up to whole boxes, because stores rarely sell partial ones.
Flooring calculator
Enter each room and the box coverage from the label.
The math
Area = length x width for each rectangle, added together. Then add 10% for cuts and waste (7% if the job is over 1,000 sq ft) or 15% for a diagonal or herringbone layout, and divide by the coverage printed on the box. Always round up.
Before you buy
- Buy all boxes from the same production lot so the color matches.
- Keep one spare box for future repairs.
- Leave flooring in the room for a day or two before installing if the maker asks you to acclimate it; check the instructions on the box.
Sources
Sources last checked 1 November 2026.
Frequently asked questions
How much extra flooring should I buy?
About 10% for a straight layout, 15% for diagonal or herringbone, according to HomeAdvisor. Big jobs over 1,000 sq ft can use about 7%.
How many boxes of flooring for a 12 x 12 room?
144 sq ft plus 10% is about 159 sq ft. At 22 sq ft a box, that is 8 boxes.