Tile Calculator

How It Works

Tiling maths is area divided by area. The calculator multiplies the length and width of your floor or wall to get the area in square feet, then works out how much area one tile covers (tile length × tile width ÷ 144). Dividing the room area by the tile area gives the exact tile count — then the waste allowance is added and the total is rounded up.

Waste is the part beginners forget: tiles at the edges must be cut, and corners, pipes and doorways all eat into your stock. Ten percent is the standard recommendation for a straight layout; diagonal patterns and rooms with many obstacles need more, which is why the percentage is yours to change.

Worked Example

A 12 ft × 10 ft floor is 120 sq ft. A 12 × 12 inch tile covers 144 ÷ 144 = 1 sq ft, so the floor needs exactly 120 tiles before waste. Adding the standard 10% gives 120 × 1.10 = 132 tiles. If tiles are sold 10 to a box, that is 132 ÷ 10 = 13.2, so you buy 14 boxes.

Assumptions

• The area is a single rectangle; split L-shaped rooms into rectangles and add the results.
• Grout lines are ignored — they make a negligible difference to the tile count.
• Waste is applied as a percentage on top of the exact count, then rounded up to whole tiles.

Tiles for a 120 sq ft room, 10% waste included:

How to Use This Calculator

Enter the length and width of the area, the tile dimensions in inches, and your waste allowance. If you know how many tiles come in a box, enter that too for the box count. Results update live.

Tips and Practical Advice

Buy all boxes in one order: dye lots can differ slightly in shade. Keep the spares — a cracked tile in two years is a quick fix if you still have matching stock, and a nightmare if the line has been discontinued. And measure the room in both directions: walls are rarely perfectly square, so use the longest length and width.