Home / Flooring & Tile
Flooring & TileFlooring Calculator — How Much Flooring or Tile Do I Need?
Enter the room’s length and width to get the finished area plus the square footage to actually buy — with a 10% waste allowance for cuts, mistakes, and future repairs.
Advertisement
How this calculator works
We multiply length × width for the room area and add 10% — the standard waste allowance for cuts, breakage, and keeping spares for repairs. Divide the "to buy" figure by your box’s coverage to get boxes.
What changes how much you need
- 10% waste suits straight layouts; use 15% for diagonal or herringbone patterns and busy rooms.
- Buy a little extra from the same lot for future repairs — colors and lots change.
- For tile, also budget thinset and grout based on tile size and spacing.
- Measure each rectangle of an L-shaped room separately and add them.
Frequently asked questions
How much extra flooring should I buy?
About 10% over the room area for standard layouts, or 15% for diagonal/herringbone patterns and complex rooms.
How do I turn square feet into boxes?
Divide the "sq ft to buy" by the coverage printed on the box (often 18–24 sq ft), then round up.
Why keep leftover flooring?
Dye lots and product lines change. A spare box from the same lot makes future repairs invisible.