Tile Calculator

Tile calculator: area, then waste

A tile calculator divides the area of the room by the area of one tile. This one assumes a 12 × 12 inch tile, which covers exactly 1 square foot, so the tile count equals the floor area. A 10 × 8 ft room is 80 sq ft and needs 80 tiles. Tick the waste box and the count becomes 88.

Tiles come in whole pieces, so the calculator rounds up.

The formula in plain words

Area = length × width, in feet. Tiles = area ÷ 1 square foot per tile. With waste, the tile count is multiplied by 1.1 and rounded up. Cost = tiles × the price per tile.

Worked example, a bedroom floor

A room measures 10 ft by 8 ft, and tiles are $2 each.

• Area: 10 × 8 = 80 sq ft
• Tiles: 80 ÷ 1 = 80
• Cost: 80 × $2 = $160
• With 10% waste: 80 × 1.1 = 88 tiles, or $176

Worked example, a bathroom floor

The bathroom is 5 ft by 8 ft, and you want the waste allowance because of the tub and toilet cuts.

• Area: 5 × 8 = 40 sq ft
• Tiles: 40
• With 10% waste: 44 tiles
• Cost at $2: $88

A small room with many cuts can use more than 10%. Ask whoever sets the tile if they want extra.

Tiles by room size

Room area	Tiles (12 × 12)	With 10% waste	Cost at $2 each, with waste
40 sq ft	40	44	$88
80 sq ft	80	88	$176
120 sq ft	120	132	$264
180 sq ft	180	198	$396
300 sq ft	300	330	$660

Using a different tile size

The calculator is built on the 12 × 12 tile. For another size, work out the area of one tile first. A 6 × 24 inch plank tile is 0.5 × 2 = 1 sq ft, so the table above applies. An 18 × 18 inch tile is 2.25 sq ft, and a 120 sq ft room needs 120 ÷ 2.25 = 53.3, so 54 tiles before waste.

Boxes matter too. Tile is sold by the box, and a box covers a set number of square feet. Divide the area by the box coverage and round up to whole boxes, then compare with the tile count.

How to measure

• Measure the length and width of the room at the floor.
• For an L-shape, split it into rectangles and add the areas.
• Include closets and alcoves that get tile.
• Subtract a tub, a built-in cabinet or anything else the tile will not go under.
• Check the room is square. If the walls are out of square by a couple of inches, add a margin for cuts.

Common mistakes

• Forgetting waste. A job that runs out of tile on the last row is stuck waiting for another box, and colors may not match.
• Using the calculator for a different tile size without adjusting.
• Measuring the wrong area, for example the floor plan outline and not the tiled area.
• Skipping layout. Plan where the cuts fall before you set the first tile, so the edges are not thin slivers.
• Not checking the carton count against the tile count.

Cartons and spares

Tile is sold in cartons, and the count per carton is printed on the box. If a carton holds 10 tiles, which is 10 sq ft of 12 × 12 tile, the 88 tiles for the bedroom make 8.8 cartons, so you buy 9. That leaves 2 spare tiles on top of the waste you already counted.

Keep those spares, together with a note of the tile’s name and lot number. If a tile cracks years from now, a piece from the same lot has the same shade. Buy all the cartons for a room at once, because stores can run out and a later batch may differ in color.

Related pages

Add the cost of labor with the tile installation cost calculator. Mortar and joints are covered by the thinset calculator and the grout calculator. For other flooring, try the flooring calculator.