Tile Calculator
Enter the area and tile size to see how many tiles and boxes to buy for a floor, backsplash or shower wall — with grout joints and cuts accounted for.
Enter the area and the tile size.
On this page
How to use the tile calculator
- Measure the area to tile. For a floor, measure wall to wall. For a wall or backsplash, measure the tiled height and width and subtract windows or cabinets.
- Choose the tile size and grout joint. Joints slightly reduce the number of tiles, which matters most for small tiles.
- Add extra for cuts: 10% for straight layouts, 15% for diagonal layouts, large-format tile or rooms with many corners.
- Enter the coverage per box to get the number of boxes.
How to calculate tile
One tile covers (sq ft) = (tile length + joint) × (tile width + joint) ÷ 144
Tiles = area ÷ one tile's coverage × (1 + extra %)
Boxes = area × (1 + extra %) ÷ coverage per box
Worked example: a 10 × 8 ft bathroom floor in 12 × 12 in tile, ⅛ in joints
- Area: 80 sq ft
- One tile with joint: 12.125 × 12.125 ÷ 144 = 1.021 sq ft
- Tiles: 80 ÷ 1.021 = 78.4, plus 10% → 87 tiles
Tiles per square foot
| Tile size | Tiles per sq ft (⅛ in joint) | For 100 sq ft + 10% |
|---|---|---|
| 3 × 6 in | 7.52 | 828 |
| 4 × 4 in | 8.46 | 931 |
| 6 × 24 in | 0.97 | 108 |
| 12 × 12 in | 0.98 | 108 |
| 12 × 24 in | 0.49 | 55 |
| 24 × 24 in | 0.25 | 28 |
Choosing a grout joint
- Rectified tiles (precisely cut edges) allow narrow joints, often 1/16 to 1/8 in.
- Pressed or handmade tiles vary in size and need wider joints, often 3/16 in or more.
- Large-format tile needs a joint wide enough to absorb small size differences; follow the manufacturer's recommendation.
Other materials to plan for
- Thinset mortar: coverage per bag depends on the trowel notch, which depends on tile size — larger tiles need a bigger notch and more mortar. Use the coverage chart on the bag.
- Grout: depends on tile size, thickness and joint width; small tiles with wide joints use far more. Grout manufacturers publish calculators for their products.
- Backer board or membrane for wet areas, and edge trim where tile meets other flooring or ends on a wall.
Frequently asked questions
How many 12 × 12 tiles do I need for 100 square feet?
About 98 with ⅛ in joints, or 108 with 10% extra for cuts.
How much extra tile should I buy?
10% for straight layouts; 15% for diagonal patterns, herringbone, large-format tile or small rooms with many cuts. Keep spares from the same lot for repairs.
Should I subtract the area under the vanity or tub?
Yes for a fixed tub or built-in cabinet. For a freestanding vanity or tub, tile underneath so it can be moved or replaced.