Tile Calculator
How many tiles and boxes you need for a floor, wall or backsplash, from the area, the tile size and an allowance for cuts.
How this is calculated
The area is length times width. Each tile covers its width times its length; with feet and inches, tile inches are divided by 12 to get feet, and with meters, tile centimeters are divided by 100. The number of tiles is the area divided by one tile's area, plus the extra allowance, rounded up to a whole tile.
The extra allowance covers tiles cut at the edges, breakage and a few spares for later repairs. About 10 percent is usual for a simple straight layout; diagonal or herringbone layouts and large tiles waste more, often 15 percent or so.
If you enter how many tiles come in a box, the boxes are the tiles divided by that number, rounded up.
Limits
A rectangular area. Grout joints are ignored, which slightly overstates the tiles needed (a little extra is useful anyway). For an L-shaped room, split it into rectangles and add the results.