How Much Do I Need?

Tile Calculator

How many tiles do I need?

Enter the size of the area, the size of one tile and the grout joint width. The calculator works out how many tiles fit, adds a waste allowance for cuts and breakage, and rounds up to whole tiles and boxes.

Units
Area to tile

For a wall, use its width and height.

For L-shaped or irregular spaces, split them into rectangles and add each one.

Tile

1/8 in = 0.125 in (about 3 mm). Enter 0 to ignore joints.

About 10% for a straight layout; 15% or more for diagonal or patterned layouts.

Leave blank if you are buying single tiles.

Cost (optional)

Add the price to see an estimated total.

Results update as you type.

Your estimate

Tiles to buy

9 boxes

87 tiles needed, including 10% waste, for 80 ft².

Estimated amount to buy

Tiles
87 tiles
Boxes (10 per box)
9 boxes
Tiles in those boxes
90

Calculated quantity (no waste)

Area to tile
80 ft² (7.43 m²)
Tile face
144 in²
Tile plus joint
147.02 in²
Tiles to cover the area
78.36
How this was calculated
  1. Area = 10 ft × 8 ft = 80 ft²
  2. Space per tile = (12 in + 0.125 in) × (12 in + 0.125 in) = 147.02 in²
  3. Tiles = 80 ft² (11,520 in²) ÷ 147.02 in² = 78.36
  4. With 10% waste = 78.36 × 1.1 = 86.2, rounded up to 87
  5. Boxes = 87 ÷ 10 per box = 8.7, rounded up to 9
  • Cut pieces at the edges can rarely be reused elsewhere, which is what the waste allowance covers.

How the tile calculation works

  1. Area = length × width of the floor or wall.
  2. Space per tile = (tile length + joint width) × (tile width + joint width). Each tile effectively takes up its own face plus one joint on two sides.
  3. Tiles = area ÷ space per tile.
  4. Add waste: tiles × (1 + waste ÷ 100), then round up to a whole tile.
  5. Boxes (optional) = tiles ÷ tiles per box, rounded up.

All measurements are converted to the same unit first, so you can enter the room in feet and the tiles in inches, or the room in metres and the tiles in centimetres.

Choosing a waste allowance

These are common rules of thumb:

  • About 10% for a straight grid in a simple rectangular room.
  • 15% or more for diagonal layouts, herringbone and other patterns, or rooms with many corners and obstacles.
  • More for large-format or fragile tiles, where one broken tile is a bigger share of the total.

Keeping a few spare tiles from the same batch makes future repairs much easier, because colours can vary between production runs.

Grout joint width

Joint widths typically range from about 1/16 in (1.5 mm) for tight wall tiles to 3/8 in (10 mm) or more for rustic floor tiles. Follow the tile manufacturer's recommendation. Wider joints mean slightly fewer tiles, and the calculator accounts for that. Enter 0 to ignore joints.

Rounding rules

  • Tiles are rounded up to a whole tile after the waste allowance is added.
  • Boxes are rounded up to a whole box.
  • The exact number of tiles that covers the area, before waste and rounding, is shown separately.