Tile is priced by the square foot but sold in boxes, and each box holds a fixed number of tiles. The calculator works from the area of a single tile, so it handles any size, from small squares to long planks. One tile maker recommends buying about 10 percent more than you expect to need, so that you have spares from the same batch if a tile cracks years later.
How to use this calculator
- Measure the floor's length and width, or a wall's width and height, in feet. For an L-shaped room, split it into rectangles, run each one and add the results.
- Enter the tile size printed on the box, such as 12x24. Use the same order every time: length first, then width.
- Leave the extra at 10 percent for a straight layout. Raise it for a diagonal or herringbone pattern, which cuts far more tiles at the edges.
- If you know how many tiles come in a box, open More options and enter it to get the number of boxes.
- Buy every box at once and check that they share the same lot number, because the shade can change from one production run to the next.
Worked examples
Small bathroom floor
Size: 5 × 8 ft · Tile: 12 × 12 in
- Tiles
- 44
- Area
- 40 sq ft
- One tile covers
- 1.00 sq ft
Kitchen floor in large tiles
Size: 12 × 14 ft · Tile: 12 × 24 in · Tiles per box: 8
- Tiles
- 93
- Boxes
- 12
- Area
- 168 sq ft
- One tile covers
- 2.00 sq ft
Tub surround wall
Size: 5 × 6 ft · Tile: 3 × 6 in
- Tiles
- 264
- Area
- 30 sq ft
- One tile covers
- 0.13 sq ft
Kitchen backsplash
Size: 12 × 1.5 ft · Tile: 3 × 6 in
- Tiles
- 159
- Area
- 18 sq ft
- One tile covers
- 0.13 sq ft
Tiles needed for common room sizes
| Room | 12 × 12 in | 12 × 24 in | 24 × 24 in |
|---|---|---|---|
| 5 × 8 ft | 44 | 22 | 11 |
| 10 × 10 ft | 110 | 55 | 28 |
| 12 × 14 ft | 185 | 93 | 47 |
| 15 × 20 ft | 330 | 165 | 83 |
Each cell: Tiles. Inputs not in the table use the calculator's starting values.
How the calculation works
The calculator multiplies the length by the width to get the area, adds the extra you set, and divides by the area of one tile. It always rounds up, because a store will not sell you part of a tile.
Grout joints are left out of the count. They take up a thin strip of every square foot, so the true number of tiles is slightly lower than the result, and that margin falls on the safe side. When you know the tile count, work out how much grout the joints will take.
Floors, walls and backsplashes
The math is the same for a wall. Enter the wall's width as the length and the height you will tile as the width. Measure a tub surround one wall at a time, because the back wall and the two end walls are rarely the same size.
A backsplash is a long, narrow strip between the counter and the upper cabinets. Measure each run separately, stop at windows and outlets only if the gap is large, and remember that small tiles mean many more cuts at the edges.
Mistakes to avoid
- Ordering exactly the floor area. Every wall, doorway and cabinet base needs cut tiles, and many offcuts are too small to use anywhere else.
- Mixing tile from different lots. A shade difference that is hard to see in the box can stand out across a finished floor.
- Forgetting closets, alcoves and the strip under a doorway. Measure every area that gets the same tile before you order.
- Comparing prices per box instead of per square foot. Boxes of different tile sizes cover different areas, so check the coverage on the label.
Tile or another floor?
If you are still choosing a floor for the room, compare the tile count with the box count for laminate or other plank flooring. Those floors are sold in cartons by the square foot, and the extra they need depends on the layout in the same way.
Common questions
How do I calculate tile for a shower?
Treat each wall as a rectangle: its width times the height you will tile. Run the calculator once per wall, or add the areas, and keep the floor separate if it uses a different tile. Showers have many cuts around corners, niches and the valve, so raise the extra above the default.
How many square feet does a box of tile cover?
It depends on the tile size and how many tiles are packed in the box, so read the label. To check it, multiply the area of one tile by the number of tiles in the box.
How much extra tile should I buy?
One tile maker recommends about 10 percent more than you expect to need, which also leaves spares from the same batch for later repairs. Diagonal and herringbone layouts cut more tiles, so plan on more for those patterns.
Do I need to account for grout lines when counting tiles?
Not for the tile count. Joints take up a small part of each square foot, so leaving them out slightly overestimates the number of tiles, which is the safe direction. Grout itself is a separate purchase that depends on the joint width and the tile thickness.
How much grout do I need for my tile?
Grout depends on the joint width, the tile size and the tile thickness. Find the volume of all the joints in cubic feet, multiply it by 110 lb per cubic foot to get pounds of sanded grout, then divide by the 25 lb bag size and round up.
How much thinset or tile adhesive do I need?
Thinset coverage depends on the trowel and the tile. For example, one maker's data sheet says a bag covers about 60 to 70 sq ft with a common quarter-by-three-eighths notched trowel. Check the coverage printed on your bag, then divide your area, including the extra, by that number and round up.