Tile Calculator
Room size, tile size and layout pattern in; tiles, full boxes and cost out. The waste allowance changes with the pattern because diagonal and herringbone layouts cut more tiles at the walls.
Why the layout changes how much tile you waste
The same room can eat very different amounts of tile. Every tile that meets a wall gets cut, and unless the offcut fits somewhere else it is waste. Drag the room size, switch to diagonal, and watch the yellow cut tiles multiply along the edges. Starting from the centre line trades one thin sliver at each wall for two balanced cuts.
This is why pros "dry-lay" a row before mixing thinset: shifting the whole grid a few inches can turn a 1-inch sliver at the doorway into two even half tiles.
How this calculator works
- Area = length × width. For L-shaped rooms, split into rectangles with the square footage calculator and add them.
- Each tile covers (tile width + joint) × (tile length + joint) ÷ 144 square feet, because the grout line takes up part of the grid.
- Area × (1 + waste %) is what you must buy. Boxes are rounded up; you cannot buy part of a box.
Tile questions
How much extra tile should I buy?
Add 10% for a straight lay, 12% for offset or brick patterns, about 15% for diagonal and 20% for herringbone or chevron. Add a few extra tiles on top for future repairs, since discontinued tile is hard to match.
How many tiles are in a square foot?
Divide 144 by the tile face area in square inches. A 12×12 tile is 1 per sq ft, 12×24 is 0.5, 6×6 is 4 and 3×6 subway is 8, before grout and waste.
Should I measure in feet or inches?
Measure wall to wall in feet and inches, convert inches to decimal feet (6 in = 0.5 ft) and enter the result. Measure at the widest point; rooms are rarely perfectly square.
Do large tiles need more waste?
Often yes. With 24×48 or larger tile, one cut near a wall can use most of a tile, and the offcut may be too small to reuse elsewhere. Lay the room out on paper first and go to the higher end of the range.