This tile calculator converts a rectangular room into a tile count using the same area method used by installers: room square footage divided by the face area of one tile, then a waste percentage for cuts and breakage.
Enter the room in feet and the tile in inches. Twelve-by-twelve tile is exactly one square foot; 12×24 tile is two square feet. A 10% waste factor is typical for straight layouts. Use about 15% for diagonals, herringbone, or rooms with many jogs.
If you know tiles per box, the result also rounds up to full boxes so you do not leave the aisle short.
If you still need the room size, start with the square foot calculator. The same walls after the floor is set often go to the wallpaper calculator, and a wet room is usually boarded with the drywall calculator before tile goes up.
How this calculation works
Room area (sq ft) ÷ tile area (sq ft) × (1 + waste). Tile area in sq ft = (length in × width in) ÷ 144. Purchase quantity is rounded up. A second layout check multiplies whole tiles along each wall.