Tile Calculator

Please fill in the required fields with values greater than 0.
–area (sq ft)
–tiles needed
–boxes needed
–tile area bought (sq ft)

Estimate only. Complex layouts need more waste. Keep a few spare tiles for repairs.

How to use this calculator

Enter the floor or wall area, the tile size and the width of the grout joint. Choose the waste allowance and press Calculate. Add the number of tiles per box to get the number of boxes.

The formula

Tile area = (tile length + grout) × (tile width + grout) ÷ 144
Tiles = area ÷ tile area × (1 + waste %)

Example: A 10 ft × 10 ft floor with 12 in tiles and a 1/8 in grout joint needs about 98 tiles. With 10% waste you need 108 tiles, which is 11 boxes of 10.

What affects how many tiles you need

The tile count from this calculator is the number of full tiles to buy, including grout space and a waste allowance. It is an ordering number, not the number of tiles that will end up uncut on the floor. Edge pieces, cuts around fixtures and a few broken tiles all come out of that extra.

Main factors that change the result

  • Tile size: Larger tiles mean fewer pieces, but each cut wastes more material. Small tiles mean more pieces and more grout lines.
  • Layout pattern: A straight grid wastes the least. Diagonal and herringbone layouts create many angled cuts at the walls, so they need more waste allowance.
  • Room shape: Bathrooms with a toilet, vanity and tub edge need more cuts than an open rectangle of the same area.
  • Grout joint: A wider joint slightly reduces the tile count, but the effect is small for joints under 1/4 inch.

A real-world example

Say you are tiling a 5 ft by 8 ft bathroom floor (40 sq ft) with 12 in by 24 in tiles and a 1/8 in grout joint. Each tile covers about 2.03 sq ft including grout, so the floor takes about 20 tiles. With 10% waste, the calculator rounds up to 22 tiles. If the tiles come 8 to a box, you need 3 boxes, which gives you 24 tiles and a couple of spares.

Tips and common mistakes

  • Measure the longest and widest points of the room. Walls are rarely perfectly square.
  • For L-shaped rooms, split the floor into rectangles, calculate each one, then add them up.
  • Do not subtract the area under a vanity unless you are sure the vanity will never move.
  • Pull tiles from several boxes as you lay them. This blends small color differences between boxes.
  • Check that every box has the same lot or shade number before you start.

Buying and planning advice

Buy all your tile at once from the same production lot. Coming back later for a few more boxes can mean a visible color mismatch. Keep at least a few spare tiles after the job for future repairs, since styles get discontinued. When you price the project, add the cost of thinset, grout, backer board or underlayment, spacers and trim pieces. These extras often add a noticeable amount to the material cost, especially for large-format tile that needs a flat, well-prepared base. Large tiles may also call for a leveling system to keep the edges even.

Frequently asked questions

How many tiles do I need?
Divide the area by the area of one tile (including the grout joint) and add 10 percent for waste.
How much waste should I allow for tile?
Allow 10 percent for straight layouts and 15 to 20 percent for diagonal layouts or small mosaic tiles.
Does grout width matter?
A little. Wider joints mean slightly fewer tiles. For narrow joints the effect is small.
How do I calculate tiles for a wall?
Use the wall height and length as the area and subtract large windows or doors.
How many tiles are in a box?
It depends on the tile. Check the label for the tiles per box and the coverage in square feet.
Should I lay out tile from the center of the room or from a wall?
Most installers start from the center of the room, or from the most visible line, and work outward. This keeps the cut pieces at the edges about the same size on both sides. Starting against a crooked wall can leave a thin sliver of tile on the opposite side. Dry-lay a row first to check where the cuts will fall.
Can I tile over existing tile?
Often yes, if the old tile is firmly bonded, flat and free of cracks. You need to clean and scuff the surface and use a thinset rated for the job. The new layer raises the floor height, which can affect doors, transitions and toilet flanges. If any old tiles sound hollow or move, remove them first.
Do I need different tile for floors and walls?
Wall tile can be thinner and softer because it does not carry foot traffic. Floor tile must handle weight and wear, and in wet areas it should offer good slip resistance. Floor tile can usually go on walls, but many wall tiles are not suitable for floors. Check the manufacturer’s rating before you buy.