Tile Calculator

The calculation itself

Area times one plus the waste fraction, divided by the area of one tile. Tile dimensions are in inches and the area in square feet, so the conversion is 144 square inches to the square foot — a 12-inch tile is exactly one square foot.

In practice

200 square feet with 10% waste is 220 square feet. At one square foot a tile, that is 220 tiles.

Halve the tile to 6 inches and its area quarters, so the same floor needs four times as many — 880. Tile count is quadratic in the tile dimension, which is why a small change in tile size changes the order so much.

The waste allowance is what decides whether you finish. Ten percent suits a straight lay in a simple room. A diagonal or herringbone, or a room with many obstacles, needs fifteen to twenty, because each cut leaves an offcut that fits nowhere else.

Why to buy beyond the waste

Batch shading. Tiles from a different production run can differ visibly in colour, and a mid-job reorder is exactly when you will get one.

Spares also cover future repairs. A cracked tile five years on is a trivial fix with a matching tile and a visible patch without one.

Large-format tiles waste more per cut because each offcut is bigger, so the usual ten percent understates a big tile in a small awkward room.

Acting on it

Set the waste from the pattern, not from habit. Straight lay and herringbone are different jobs.

Buy full boxes from one batch and keep the spares. The box count matters more than the tile count at the till.

Dry-lay a row before fixing anything, to see where the cuts land. Moving the starting line can remove a whole row of awkward cuts.