You enter the area dimensions in feet, the tile size in inches, grout line width, and a waste percentage. The tool adds grout spacing to the tile dimension, calculates effective tiles per square foot (144 ÷ tile-with-grout²), multiplies by total area, applies the waste factor, and rounds up. Boxes assume 10 tiles each. It does not account for diagonal layouts or non-square tiles, which typically require more waste.
Ten percent is standard for straight layouts in rectangular rooms. Diagonal patterns, herringbone, or rooms with many cuts (around toilets, doorways, cabinets) should use 15%. Complex patterns or irregular spaces may need up to 20%.
For most floor tiles, 1/8 inch (0.125 in) is a common grout line width. Large-format tiles (18" and above) often use 1/16 inch, while natural stone may use 3/16 inch. The tile manufacturer usually recommends a specific spacing.
This calculator assumes square tiles. For rectangular tiles, a more precise calculation would account for different row and column spacing. As an approximation, you can use the tile's shorter dimension and increase the waste factor to 15–20%.
Tile production runs (dye lots) vary slightly in color and finish. If a tile cracks or chips years later, replacement tiles from a new batch may not match exactly. Keeping a few spares from the original purchase ensures a perfect match for repairs.
Estimate only. Results reflect your inputs and standard formulas. Double-check important decisions independently.