Tile Calculator

How the count works

The tile count starts with area: length times width in square feet. Each tile covers its own area — a 12 by 12 inch tile covers exactly 1 square foot, a 12 by 24 covers 2. Divide the room area by the tile area and round up: that is the number of whole tiles. Then add the waste factor, which covers cuts at the edges, broken tiles and the pieces that do not fit anywhere else. Ten percent is the standard for a straight grid layout; diagonal layouts need 15%, and a room with many angles, niches or a diagonal pattern can need 20%. Finally divide by the tiles per box and round up — you cannot buy part of a box.

Why waste matters

The waste factor is the line that separates a finished job from a second trip to the store. Edge cuts alone consume roughly 5% of the tiles in a rectangular room, and every cut is a chance to break a tile. A diagonal layout wastes more because every edge tile is cut at an angle. The most expensive version of this mistake is running out of a discontinued tile halfway through: buy the extra box now, keep the receipt, and return unopened boxes later. An unopened box costs nothing to return; a missing box costs a week.

Before you order

Measure the room at its widest points, including under the toe-kick and into doorways — the area you tile is bigger than the area you walk on. Check the dye lot on every box: tiles from different lots can differ visibly in shade, and the store will not take back an opened box. For large-format tiles, check the floor is flat to within the manufacturer's tolerance; a 24-inch tile on a wavy floor will lip at the edges no matter how good the installation is.

Frequently asked questions

How many tiles do I need for a 10×12 room?

120 square feet. With 12×12 inch tiles (1 sq ft each) that is 120 tiles, or 132 with a 10% waste factor — 17 boxes at 8 tiles per box. Enter your exact room and tile size above.

What waste factor should I use for tile?

10% for a straight grid, 15% for a diagonal layout, and 15–20% for rooms with many angles, niches or obstacles. Large-format tiles and patterned layouts sit at the high end.

Why do I need tiles from the same dye lot?

Tiles are fired in batches, and the shade can vary slightly between batches. Two lots on one floor can show a visible line. Check the lot number on every box before you leave the store.