Tile Calculator
Find how many tiles and boxes you need for a floor, shower wall or backsplash.
How to use this tile calculator
Measure the area you're tiling in feet. For a wall or backsplash, use the width and the height. Enter the tile's size in inches and the square feet per box from the product label, then pick your layout. Patterns with more angled cuts waste more tile, so the waste allowance goes up with them.
For a shower or a room with a jog, split it into rectangles and add the results together. Subtract large areas you won't tile, like a bathtub or a kitchen island.
Common tile sizes
| Tile | Sq ft per tile | Tiles per 100 sq ft |
|---|---|---|
| 3 × 6 in subway | 0.125 | 800 |
| 6 × 24 in plank | 1.0 | 100 |
| 12 × 12 in | 1.0 | 100 |
| 12 × 24 in | 2.0 | 50 |
| 24 × 24 in | 4.0 | 25 |
These counts don't include grout lines. Grout makes each tile cover very slightly more, so the real count comes out a little lower. That's a small bonus on top of your waste allowance.
The math behind it
Area to buy = length × width × (1 + waste%). Tiles = area to buy × 144 ÷ (tile width × tile length), rounded up. Boxes = area to buy ÷ sq ft per box, rounded up.
Example: an 8 × 10 ft bathroom floor is 80 sq ft. With 10% extra it's 88 sq ft, which is 88 tiles at 12 × 12 inches, or 9 boxes at 10 sq ft each.
Don't forget
- Thinset mortar: a 50 lb bag covers roughly 40–90 sq ft depending on the trowel notch size, so check the bag.
- Grout, spacers and backer board for floors or wet areas.
- Spare tiles: keep a few for future repairs, because discontinued tile can be impossible to match.
Often used together
Quick answers
How many tiles do I need for 100 square feet?
100 tiles of 12 × 12 inches, 50 tiles of 12 × 24 inches, or 800 subway tiles of 3 × 6 inches, plus 10–15% extra for cuts.
How much extra tile should I buy?
10% for a straight grid, 15% for offset or diagonal layouts, and around 20% for herringbone. Keep a few spares for future repairs.
Does grout spacing change how many tiles I need?
Only slightly. Grout lines make each tile cover a little more area, so you'll need a few less tiles than the basic count, which leaves a bit more spare.