Tile Calculator

Divide the area by the area of one tile, then add a waste factor. A 12 × 12 in tile is exactly 1 sq ft, a 12 × 24 is 2 sq ft, and a 6 × 6 is a quarter of a square foot — which is why small formats drive the piece count up so fast. Grout lines are narrow enough that layout math normally ignores them.

With 12 × 12 in tile and a 10% waste factor you need 132 tiles. At 10 tiles per box that rounds to 14 boxes, or 140 tiles — so the true surplus is about 17%, not 10%. That extra isn't wasted money: the leftovers are your repair stock, and unopened boxes are usually returnable.

Ten percent covers a straight grid layout in a simple rectangular room. Use 15% for a diagonal or offset pattern, 20% or more for herringbone and chevron, and add a few points for rooms with many corners, alcoves, or a curved edge. Large-format tile also raises waste, because each bad cut ruins more square footage.

Stores sell boxes, not individual tiles, and color varies measurably between production runs. Buy every box in one order with matching lot numbers, and keep four or five spares after the job — a cracked tile then becomes a 20-minute repair instead of a re-floor. Check the box for its actual square footage rather than trusting the tile count, since ceramic sizes are nominal.

Thin-set mortar coverage depends on trowel notch and tile size: roughly 80–100 sq ft per 50 lb bag with a quarter-inch notch, and far less under large-format tile that needs back-buttering. Grout runs about 1 lb per 10 sq ft for narrow joints on small tile. Neither scales with tile count, so size them from the area instead.