How to use the tile calculator
- Pick your units. Feet and inches, or meters and centimeters.
- Measure the area. Enter the floor length and width, or the wall run and the height you are tiling.
- Enter the tile size and grout gap. Use the real tile size from the box and the joint you plan, often 1/8 in on floors and 1/16 in on walls.
- Pick the layout. Straight adds 10 percent for cuts, brick or offset 15 percent, diagonal or herringbone 20 percent.
- Add the box size. Enter tiles per box and the price to see how many boxes to buy and the cost.
How to calculate how many tiles you need
Tile quantities come down to two numbers: the area you are covering and the space one tile takes up, including its share of the grout joint. The calculator does the math, but here is how it works so you can double check.
- Measure the area. Multiply length by width. A 10 by 12 foot bathroom floor is 120 square feet. For a backsplash, multiply the run of countertop by the height you are tiling.
- Size one tile with grout. Add the grout gap to each side measurement. A 12 inch tile with a 1/8 inch joint takes up 12.125 by 12.125 inches, about 147 square inches.
- Divide. 120 square feet is 17,280 square inches, and 17,280 divided by 147 is about 118 tiles.
- Add waste. Add 10 percent for a straight layout, taking you to 130 tiles, then divide by the tiles per box and round up.
Worked examples: tiles for real projects
Real results from the calculator for common jobs.
| Project | Area | Tile and grout | Layout | Tiles to buy |
|---|---|---|---|---|
| Bathroom floor | 10 x 12 ft, 120 sq ft | 12 x 12 in, 1/8 in | Straight, 10% | 130 tiles (13 boxes of 10) |
| Room floor | 12 x 12 ft, 144 sq ft | 12 x 12 in, 1/8 in | Straight, 10% | 156 tiles (16 boxes of 10) |
| Diagonal floor | 10 x 10 ft, 100 sq ft | 12 x 12 in, 1/8 in | Diagonal, 20% | 118 tiles |
| Small bathroom floor | 5 x 8 ft, 40 sq ft | 12 x 24 in, 1/8 in | Offset, 15% | 23 tiles |
| Kitchen backsplash | 10 ft run, 18 in high, 15 sq ft | 3 x 6 in subway, 1/16 in | Brick, 15% | 134 tiles |
| Tub surround | 3 walls, 10 ft total, 6 ft high, 60 sq ft | 3 x 6 in subway, 1/16 in | Brick, 15% | 536 tiles |
| Shower walls | 13 ft of wall, 8 ft high, 104 sq ft | 4 x 12 in, 1/16 in | Brick, 15% | 352 tiles |
Small tiles add up fast: a 15 sq ft backsplash takes 134 subway tiles, and a 60 sq ft tub surround more than 500. Subway and mosaic tiles are often sold by the square foot, so check what one box covers.
How much extra tile should I buy?
| Layout | Extra | Why |
|---|---|---|
| Straight or grid | 10% | Cuts along the edges and a few breakages |
| Brick, offset or staggered | 15% | Every other row starts with a cut tile |
| Diagonal or herringbone | 20% | Angled cuts at every edge |
| Large format or natural stone | 15 to 20% | Fewer tiles per cut, more variation to sort through |
Choosing a grout gap
Floors usually use a 1/8 inch (3 mm) joint, while wall tiles and backsplashes often go tighter at 1/16 inch (1.5 to 2 mm). Rectified tiles with crisp, machine cut edges can go tighter still, while handmade and rustic tiles need wider joints to hide size differences. The gap makes a real difference to the count on small tiles such as mosaics and subway tiles, so enter the one you plan to use.
Floors, showers and backsplashes
For a shower, measure each wall separately and add them together, then add the floor if you are tiling it too. For a kitchen backsplash, measure the length of each run of countertop and the height to the bottom of the wall cabinets, usually around 18 inches. For flooring in other materials, try the flooring calculator. Find inspiration in our luxury bathroom ideas and small kitchen design ideas.
