Tile Calculator — number of tiles for an area

How it works

To tile a floor or wall, divide the area to cover by the area of a single tile, adding a waste allowance for cuts:

tiles = ⌈area × (1 + waste) ÷ tile area⌉

A tile's area is its width × height in inches, divided by 144 to convert to square feet (since 12 × 12 = 144 square inches make one square foot). Enter the tile size and the calculator works out the rest.

A 10% waste allowance is standard; use 15% for diagonal layouts, small mosaic tiles, or rooms with many cuts and corners. The result rounds up to whole tiles — and keeping a few spares for future repairs is always sensible, since matching a discontinued tile later is difficult.

Worked example

100 sq ft of 12 × 12 inch tiles — each 1 square foot — with 10% waste needs (100 × 1.1) ÷ 1 = 110 tiles. Small 3 × 6 inch subway tiles (0.125 sq ft each) covering 60 sq ft need ⌈66 ÷ 0.125⌉ = 528 tiles. Large-format 24 × 24 inch tiles (4 sq ft each) for 100 sq ft need only ⌈110 ÷ 4⌉ = 28 tiles.

Frequently asked questions

How many tiles do I need?

Divide the area (plus waste) by the area of one tile and round up. The tile area is its width × height in inches ÷ 144 to get square feet. For 100 sq ft of 12×12 tiles with 10% waste, that is 110 tiles.

How do I convert a tile's inch dimensions to square feet?

Multiply the width by the height in inches, then divide by 144 (because 144 square inches make one square foot). A 12 × 12 tile is 144 ÷ 144 = 1 sq ft; a 6 × 6 tile is 36 ÷ 144 = 0.25 sq ft.

How much waste should I allow for tile?

About 10% for a standard straight or grid layout. Diagonal and herringbone patterns, mosaics, and rooms with lots of cuts around fixtures need 15% or more. Larger tiles in a simple room can get by with a bit less.

Why keep spare tiles?

Tile colors and lots change between production runs, so a tile bought later may not match. Setting aside a few spares from the original batch means you can replace a cracked tile with an exact match years down the line.

Does tile size change how many I need?

Greatly — a larger tile covers more area each, so you need far fewer. The same 100 sq ft takes 110 twelve-inch tiles but only 28 large 24-inch tiles. Small tiles also waste more at cuts, so their effective count climbs faster.

Does this include grout, spacers or adhesive?

No — it counts the tiles only. Grout and thin-set adhesive are estimated from the area and tile size (smaller tiles mean more grout lines), and spacers by the tile count. Calculate those separately.