Tile Calculator

Tiles are sold by the box, so an estimate has to end with a whole number of boxes. The calculator divides your floor area by the area of one tile, adds a waste allowance for cuts and breakage, then converts the tile count into boxes using either the number of tiles per box or the coverage printed on the box.

It works for floors, walls and backsplashes. For a wall, enter its width and height instead of length and width.

1. Enter the length and width of the area to tile.
2. Enter the tile size. Use the nominal size from the box (for example 12 × 24 in or 600 × 300 mm).
3. Set the waste allowance for your layout.
4. Choose whether your box lists tiles per box or square feet / square metres per box, and enter that figure.
5. Optionally add the price per box.

Floor area = Length × Width

Tile area = Tile length × Tile width

Tiles = Floor area × (1 + Waste % ÷ 100) ÷ Tile area, rounded up

Boxes = Tiles ÷ Tiles per box, rounded up

Floor area and tile area must be in the same unit. A 12 × 12 in tile is 144 sq in = 1 sq ft; a 600 × 300 mm tile is 0.18 m². The calculator converts for you, so you can enter the room in feet and the tile in inches, or the room in metres and the tile in millimetres.

A 12 ft × 10 ft kitchen floor with 12 × 24 in tiles, 8 tiles per box:

• Floor area: 12 × 10 = 120 sq ft
• Tile area: 1 ft × 2 ft = 2 sq ft
• Tiles without waste: 120 ÷ 2 = 60
• With 10% waste: 132 ÷ 2 = 66 tiles
• Boxes: 66 ÷ 8 = 8.25 → 9 boxes (72 tiles, 144 sq ft)

Metric: a 3.6 m × 3.0 m floor is 10.8 m². With 600 × 300 mm tiles (0.18 m² each) that is 60 tiles, or 66 with 10% waste. That’s 9 boxes of 8.

• Boxes to buy – the tile count with waste, rounded up to full boxes.
• Tiles without waste – the minimum number to cover the area if nothing were cut or broken.
• Extra tiles – the waste allowance in tiles.
• Area purchased – how much tile the boxes actually contain; usually a little more than you need.

• Check that all boxes share the same batch or lot number; shade can vary between production runs.
• Large-format tiles and natural stone often break more during cutting; consider a higher allowance.
• Measure out-of-square rooms at both ends and use the larger figure.
• Keep a few spare tiles. Finding an exact match years later can be difficult.

These are common rules of thumb, not fixed standards. Your installer may recommend a different figure for the tile and room. For the joint filler, use the grout calculator; to add up several rooms first, use the square footage calculator.