Tile Calculator
Calculate the number of tiles needed for a room given the room size, tile size and waste factor.
- Tiles to Cover Room120 tiles · 91%
- Waste / Cut Allowance12 tiles · 9%
Buying only the base tile count leaves nothing for cuts around edges and breakage — the 10% waste allowance covers that so you don't have to make a second trip.
About the Tile Calculator
This calculator works out how many tiles a floor or wall job needs, based on room dimensions, individual tile size, and a waste allowance for cuts and breakage — the number to have before standing in a tile aisle guessing at boxes.
It's used before a bathroom, kitchen backsplash, or flooring retile — sizing a materials order so you buy enough in one trip without wildly overbuying, especially useful since tile is sold by the box and running short mid-job on a specific batch or dye lot can mean a mismatched replacement.
Enter the room's length and width along with the individual tile's dimensions, and it converts everything to a common unit before dividing — plus a waste percentage on top for the pieces lost to edge cuts and the occasional cracked tile.
How it’s calculated
Room area (length × width, in square feet) is divided by each tile's area (converted from inches to square feet by multiplying tile length × width and dividing by 144) to get the base number of tiles needed to cover the floor with no cuts or breakage.
The waste percentage is added on top of that base count to cover tiles cut at the edges of the room (which rarely use a full tile) and the inevitable breakage that happens during cutting and installation — skipping this allowance is a common reason DIY tile jobs come up short right at the finish line.
Frequently asked questions
How much waste allowance should I add for tile?
10% is a reasonable default for a simple rectangular room laid in a straight pattern; more complex layouts (diagonal patterns, herringbone, lots of corners or fixtures to cut around) commonly need 15% or more.
Should I round the tile count up to full boxes?
Yes — tile is sold by the box, and this calculator's result is the raw tile count. Check how many tiles come per box from the product you're buying and round up to the next full box, since buying loose individual tiles usually isn't an option.
Does grout line width affect how many tiles I need?
Not significantly for the tile count itself — grout lines take up a small amount of space between tiles, but the effect on total tile count is minor compared to the waste factor for cuts. It matters more for grout quantity than for tile quantity.
What if my room isn't a perfect rectangle?
Split the room into rectangular sections, run each through the calculator separately, and add the tile counts together — that keeps the area math accurate for irregular layouts like L-shaped bathrooms or rooms with alcoves.
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