Tile Calculator: How Many Tiles Do I Need?
Count the floor tiles to buy from your area, a waste factor and the tile size — rounded up to whole tiles, with a spare allowance for cuts and breakage.
Calculator
A 100 sq ft floor at 10% waste in 2.00 sq ft tiles is about 55 tiles. Confirm the coverage on the box and buy a spare box for cuts, waste and future repairs — dye lots change.
Tile is bought by the piece (or by the box of pieces), so the useful answer to how many tiles do I need? is a whole-tile count that already includes waste. This calculator grows your floor area by a labeled waste factor, divides by the square footage of one tile, and rounds up.
Pick the tile size from the list — a 12 × 12 in tile is 1 sq ft, a 12 × 24 in tile is 2 sq ft, and a 24 × 24 in tile is 4 sq ft. Tile waste runs a touch higher than plank flooring because cut tiles rarely reuse cleanly and a few crack during handling and cutting, so a spare box is standard practice. For the layout-and-count view and a pattern discussion, see the tile layout & count calculator.
Formula
tiles = ceil(area_sqft × (1 + waste%) ÷ tile_sqft)
Grow the area by the waste factor, divide by the coverage of a single tile, and round up with a ceiling. The tile size (sq ft each) comes from the tile’s nominal dimensions: length × width ÷ 144. Waste and tile size are both adjustable so the count matches your real product.
Worked example
A 100 sq ft floor at a 10% waste factor in 12 × 24 in tiles (2 sq ft each):
- Area with waste = 100 × (1 + 0.10) = 110 sq ft
- Tiles = ceil(110 ÷ 2) = 55 tiles
So 55 tiles for a 100 sq ft floor. Switch to 12 × 12 in tiles (1 sq ft) and you’d need ceil(110 ÷ 1) = 110 tiles; go to 24 × 24 in (4 sq ft) and it’s ceil(110 ÷ 4) = 28 tiles. Bigger tiles mean fewer pieces but each cut wastes more, so keep the waste factor honest.
Waste, breakage and dye lots
Buy a full spare box beyond the calculated count. Cut tiles at the walls seldom yield a usable off-cut, diagonal and herringbone layouts waste more, and tiles from a different production run can differ subtly in shade — a same-lot spare saves a future repair from standing out. Once you know the tile count, size the setting materials with the thinset & mortar coverage calculator and the grout calculator.
This is a tile-quantity estimate, not a bid: confirm the coverage on the box, since nominal and actual tile sizes differ slightly and boxes vary by brand. See common tile sizes and the cost-to-tile-a-floor guide for the full picture.