How it works
Tiles are sold by the piece, but you buy by the area. Divide the floor area by the area of one tile to get the exact count, then add 10% — cuts at edges and corners, plus the odd broken tile, always use more than the exact number.
The 10% allowance is the trade standard for straight layouts. For a diagonal or herringbone pattern, allow 15% instead.
Formula
Floor area = length × width. Tiles needed = floor area ÷ area of one tile, plus 10% extra for cuts and breakage, rounded up.
What each input means
- Floor length: The length of the floor, in feet.
- Floor width: The width of the floor, in feet.
- Tile length: The length of one tile, in inches.
- Tile width: The width of one tile, in inches.
- Floor length: The length of the floor, in metres.
- Floor width: The width of the floor, in metres.
- Tile length: The length of one tile, in centimetres.
- Tile width: The width of one tile, in centimetres.
Worked example: 12 ft × 10 ft floor, 12 in × 12 in tiles
- Floor area: 12 × 10 = 120 sq ft
- One tile: 12 × 12 in = 1 sq ft
- Exact count: 120 ÷ 1 = 120 tiles
- With 10% for cuts and breakage: 120 × 1.10 = 132 tiles
Frequently asked questions
Why add 10% extra?
Tiles at the edges must be cut, and a few always break. The 10% allowance covers cuts and breakage for a straight layout; use 15% for diagonal patterns.
Do I need to subtract fixtures?
For a bath or toilet footprint, subtract it only if it is large. Small fixtures are usually ignored — the tiles under them are covered by the 10% allowance.
How do I count tiles for a wall?
The same way: wall area divided by tile area, plus 10%. Measure each wall separately and add them up.
What size tile should I choose?
Large tiles (12×24 in and up) make small rooms look bigger and have fewer grout lines, but they are harder to cut and cost more per piece.