Tile Calculator

How Many Tiles Do I Need?

Tile estimates come down to two numbers: the area you’re covering and the area one tile covers. Divide one by the other, add a waste allowance for cuts and breakage, and round up to full boxes. The calculator does it as you type. Below is the long-hand version.

How to Calculate Tile by Hand

1. Area to tile

Area (ft²) = length (ft) × width (ft)

For walls, use the wall’s width × the height you’re tiling to. For a backsplash, measure the length of the counter run × the height up to the cabinets.

2. Area of one tile

Tile area (ft²) = tile length (in) × tile width (in) ÷ 144

A 12 × 12 tile is 1 ft². A 12 × 24 is 2 ft². A 3 × 6 subway tile is 0.125 ft².

3. Tiles and boxes

Tiles = area ÷ tile area × (1 + waste), rounded up Boxes = tiles ÷ tiles per box, rounded up

Worked example: a small bathroom floor on the diagonal

The floor is 5 × 8 feet, laid with 12 × 24 inch porcelain on a diagonal, and the boxes hold 8 tiles:

• Floor area: 5 × 8 = 40 ft²
• Tile area: 12 × 24 ÷ 144 = 2 ft²
• Tiles before waste: 40 ÷ 2 = 20
• With 15% diagonal waste: 20 × 1.15 = 23 tiles
• Boxes: 23 ÷ 8 = 2.9, rounded up to 3 boxes (one spare tile)

Worked example: a subway tile backsplash

A 10 foot counter run with tile 3 feet up to the cabinets is 30 ft². With 3 × 6 inch subway tile at 0.125 ft² each, that’s 240 tiles before waste. Add 10% for cuts around outlets and the window to get 264 tiles.

Tips & Common Mistakes

Small rooms waste more

In a powder room or shower, a large share of tiles touch an edge and need cutting. Bump waste up to 15–20% there, even for a straight lay. Big open floors with few obstacles can get by with less.

Large-format tile is unforgiving

Large tiles leave big offcuts that often can’t be reused, and one cracked tile is an expensive loss. Order a little more than you think. Plan the layout before you set anything so you don’t end up with thin slivers at a wall.

Do a dry layout first

Lay a row of tiles along the longest wall before mixing any thinset. Shift the starting line so the cut pieces at both ends are roughly equal and at least half a tile wide. This takes ten minutes and saves tile.

Keep a spare box

Store leftovers somewhere dry and labeled with the room. Discontinued tile is often impossible to match, and one cracked tile in the middle of a floor is a lot easier to fix with an original spare.

Don’t forget what goes under the tile

This calculator covers the tile itself. Thinset, grout, backer board and membrane each have their own coverage charts on the package, and they depend on trowel size and joint width. For laminate, vinyl plank or hardwood, use our flooring calculator instead.