Tile Calculator
Find how many tiles and boxes you need for a floor or shower wall, with a waste allowance for cuts and breakage.
Use 10% waste for a straight layout, 15% for diagonal or herringbone patterns with more cuts. Always round up to whole boxes and keep a spare box or two for future repairs.
How it works
Enter the area you're tiling in square feet, the size of a single tile in inches, and a waste percentage for cuts and breakage. The calculator converts your area to square inches, divides by the tile's footprint to get a raw tile count, then adds the waste allowance and rounds up, since a partial tile still means buying a whole one. If you know how many tiles come in a box, add that too and it will tell you how many boxes to buy.
Worked example: an 80 sq ft floor with 12x12 in tiles and 10% waste. That's 80 × 144 ÷ 144 = 80 tiles before waste, then 80 × 1.10 = 88, so the calculator lands on 88 tiles. At 10 tiles per box, that's 9 boxes, which cover 88 sq ft once laid, a bit more than the room itself to cover the waste. Switch the same 80 sq ft to a 3x6 in subway tile and the count jumps to 704 tiles, since each tile covers far less area. That's the main reason small-format tile and mosaic sheets cost more to install per square foot: you're buying and setting a lot more pieces for the same room.
FAQ
How much waste percentage should I use?
10% covers most straight, grid-pattern layouts. Bump it to 15% for diagonal layouts, herringbone, or any room with a lot of odd angles, since more cuts mean more tiles get wasted or saved as unusable offcuts.
Should I round up to a full box even if I only need a few more tiles?
Yes. Dye lots vary between production runs, so a box you buy later to top up a shortage might not match the color of what's already on the wall or floor. Buying enough boxes up front, with the waste allowance built in, avoids that mismatch.
Does this work for shower walls as well as floors?
Yes, just measure the wall area you're tiling (height times width, minus the shower pan and any fixtures you're not tiling around) and use that as your area input. Wall tile projects often use a smaller tile size, so double check the width and height you enter match the tile you're actually buying.
What if I have leftover tile from a previous project?
Subtract what you already have from the calculated total before ordering. Keep in mind older tile may be from a different dye lot, so it's often best used in a less-visible spot like behind a toilet or under a vanity.
For more on choosing and installing tile, see how to tile a shower wall, how to choose bathroom floor tile that lasts, and porcelain vs. ceramic tile.