Tile Calculator
Calculate how many tiles you need for a floor or wall, including a waste allowance for cuts and breakage.
What this calculates
Buying tiles is one of the few home-improvement purchases where running short is genuinely painful — dye lots change between production runs and you may not be able to match the rest of your floor. This calculator gives you the tile count for any surface, with a configurable waste allowance for cuts, edges, and breakage during install.
Formula & how it works
Tile count = ceil((surface_area ÷ tile_area) × (1 + waste_percent ÷ 100)). For square or rectangular tiles in inches: tile_area = length × width ÷ 144 sq ft. Surface area is usually room length × width. For complex shapes, split into rectangles and sum. Standard waste allowances: 10 % for simple straight layouts, 15 % for diagonal or herringbone, 20 % for very small (mosaic) tiles.
Worked example
A 10 × 12 ft bathroom floor with 12 × 12 in tiles. Surface = 120 sq ft. Tile area = 144 ÷ 144 = 1 sq ft. Need 120 tiles plus 10 % waste = ceil(132) = 132 tiles. If the tiles come in boxes of 10, buy 14 boxes (140 tiles).
Frequently asked questions
Why so much waste allowance?
Cuts at walls and corners produce unusable scraps. Tiles break during install. Pattern alignment forces extra cuts. 10 % is the safe floor; complex layouts can hit 20 %+. Better to have leftovers (use as future repair stock) than run short.
How do I account for grout lines?
Tile dimensions usually include the grout joint (the nominal size). If you're measuring the 'actual' tile body, add 1/8 to 3/8 inch to each dimension for the grout. The calculator assumes nominal sizing, which is how tiles are sold.
Should I order extra for future repairs?
Yes — at least 5 % extra beyond the waste allowance. Tiles get discontinued and dye lots shift. Having a few originals stored away can save a whole-floor replacement years later.
What about hexagonal or irregular tiles?
Use the manufacturer's coverage figure (often sq ft per box). Custom shapes need higher waste — 15–20 %. Mosaic sheets are usually sold by the sheet; calculate by sheet area instead of individual tiles.