Buying tiles by guesswork is how most people end up one box short in the middle of a job — or with a stack of spares nobody wants. This free tile calculator works it out properly: enter your floor size and tile size, add a sensible allowance for cuts and breakages, and it tells you exactly how many tiles (and boxes) to buy.
Tile Calculator
10% is a safe default for straight layouts. Use 15% for diagonal patterns or rooms with lots of corners.
How to use it
- Measure the longest length and width of the floor in feet. For L-shaped rooms, split the floor into two rectangles, work each one out, and add the areas together.
- Enter your tile size in inches — the size printed on the box, for example 12 x 12 or 24 x 12.
- Keep the wastage allowance at 10% for a straight layout, or raise it to 15% for diagonal laying or awkward corners.
- Enter how many tiles come in one box, then press Calculate. Buy the full number of boxes shown — never round down.
Worked example
A 12 x 10 foot room is 120 sq ft. With 12 x 12 inch tiles (1 sq ft each) and 10% wastage, you need 132 tiles. At 10 tiles per box, that is 14 boxes.
Tips before you buy
- Always keep a few spare tiles from the same batch — a later batch can differ slightly in shade.
- Measure twice, including doorways and alcoves, before ordering.
- If your room is not a perfect rectangle, measure the largest length and width and let the wastage allowance cover the offcuts.
Frequently asked questions
How much wastage should I add?
10% for straight layouts, 15% for diagonal or complex rooms.
Do I need to subtract doors or fixtures?
For floors, no — the wastage allowance already covers small cut-outs. Only subtract very large fixed areas.
What if my tiles are in centimetres?
Convert first: 1 inch = 2.54 cm. A 30 x 30 cm tile is about 11.8 x 11.8 inches.