Tile Calculator
Calculate tile count from room and tile size, grout gap, and waste percentage.
Written by Golam Rabbani, Founder & Lead Engineer
How to use this tile calculator
- Toggle between imperial (ft / in) and metric (m / cm).
- Enter the room length and width, then the individual tile length and width.
- Optionally add a grout gap and the waste percentage you want to keep on hand.
- Press Calculate to see the total tile count, including waste.
- Use Copy to save the estimate or Reset to start over.
About this tile calculator
The tile calculator finds how many tiles you need to cover a rectangular floor or wall. It divides the room area by the effective footprint of a single tile (tile size plus grout gap on two sides), then multiplies by 1 plus your waste percentage. Standard practice is 10% waste for a straight grid layout and 15% for a diagonal or herringbone pattern.
Worked example: a 12 ft × 10 ft bathroom is 120 ft². With 12-inch square tiles and a 1/8-inch grout gap, each tile occupies 12.125 in × 12.125 in ≈ 147 in² = 1.021 ft² of floor when the grout footprint is included. Dividing 120 ft² by 1.021 ft² gives 117.5 exact tiles. Add 10% waste: 117.5 × 1.10 = 129.25, rounded up to 130 tiles.
Waste covers cuts at the walls, breakage during installation, and future repairs. If you are tiling an L-shape or odd shape, split the floor into rectangles, run the calculator on each, and add the results — then add an extra box for spare matching tiles, since dye-lot numbers vary between production runs.
FAQ
- How much waste should I add for tile?
- Use 10% for a standard straight (grid) layout on a rectangular floor. Bump to 15% for diagonal or herringbone patterns, and 20% for complex tiles like hexagons or layouts with many small cuts.
- Does the grout gap really change the count?
- Yes — for small tiles. A 1/8″ grout joint on a 12″ tile only changes the footprint by ~2%. On a 4″ subway tile, the same joint changes the footprint by ~6%, which can easily mean a whole extra box.
- Why round up to whole tiles instead of fractional?
- Tiles are sold by the piece (or by the box). You cannot buy half a tile, so the calculator rounds up after the waste calculation to give you a buy-it count.
- Does this work for wall tile too?
- Yes. Use the wall length and wall height in place of room length and width. The math is identical.
- What if my room is not a rectangle?
- Split the floor plan into rectangles, run the calculator for each section, and add the tile counts. Add at least one extra box to account for the extra cuts at internal corners.
- Is the calculator free?
- Yes — free, no signup, runs entirely in your browser.