Tile Calculator
Instantly estimate exactly how many tiles and boxes you need for your floor, wall, or backsplash. Our calculator factors in standard grout lines and waste limits.
Whether you are tiling a kitchen backsplash, laying down large-format bathroom floors, or updating a shower wall, ordering the exact right amount of tile is critical. Ordering too few means pausing your project—and risking that the next batch of tiles won’t perfectly match the color dye lot of the first batch.
Our tile calculator eliminates the guesswork. By converting your project’s dimensions and the exact size of your chosen tile (including the grout joints), it instantly calculates the total number of tiles, the number of boxes you need to buy, and the estimated material cost.
How to Calculate How Many Tiles You Need
To accurately estimate your tile needs, you must find the total area of your project, divide it by the area of a single tile, and then add a percentage for waste. Here is the mathematical process used by professional contractors:
- Find Total Project Area: Measure the length and width of the floor or wall. Multiply them together. (e.g., A 10 ft by 12 ft room = 120 square feet).
- Find the Tile Area: Measure the length and width of a single tile. If measuring in inches, multiply them together and divide by 144 to convert to square feet. (e.g., A 12×24 inch tile is 288 sq inches. 288 ÷ 144 = 2.0 square feet).
- Divide to Find Raw Tiles: Divide the total project area by the tile area. (120 sq ft ÷ 2.0 sq ft = 60 tiles).
- Add Waste Factor: Multiply the raw tile count by 1.10 to add a 10% waste margin for cuts. (60 × 1.10 = 66 tiles).
Total Tiles = (Project Area ÷ Tile Area) × (1 + Waste Factor)
What is the 10% Waste Rule?
A frequent mistake DIYers make is buying the exact mathematical amount of tile. You must assume that tiles will break, that you will miscut edges, and that you will need to slice tiles in half to fit against the walls.
The industry standard is to order 10% extra tile for waste on simple square or rectangular rooms. However, the waste factor increases depending on your layout:
- 10% Waste: Standard straight-lay patterns in square rooms.
- 15% Waste: Complex rooms with many cabinets, corners, or if laying tile in a diagonal or staggered pattern.
- 20% Waste: Highly complex custom layouts (like herringbone) or when working with very large format tiles where a single mistake ruins a massive piece.
Calculating Tiles for a Backsplash or Shower
If you are tiling a kitchen backsplash or a shower enclosure, the process is the same, but the dimensions are smaller. Backsplashes are usually measured in inches rather than feet.
Measure the width of the wall space under your cabinets in inches, and measure the height (usually 18 inches standard). Multiply them together, then divide by 144 to get the square footage. Use our calculator above by entering the final square footage directly into the Area input.
Standard Tile Sizes and Coverage
Having uniform shape size makes calculations easier. If you are shopping for tile, here is a quick reference for how many square feet common tile sizes cover (excluding grout):
| Tile Size (Inches) | Square Footage per Tile | Tiles Needed per 100 sq ft (incl. 10% waste) |
|---|---|---|
| 3″ x 6″ (Subway) | 0.125 sq ft | 880 tiles |
| 6″ x 6″ | 0.25 sq ft | 440 tiles |
| 12″ x 12″ | 1.00 sq ft | 110 tiles |
| 12″ x 24″ | 2.00 sq ft | 55 tiles |
| 18″ x 18″ | 2.25 sq ft | 49 tiles |
| 24″ x 24″ | 4.00 sq ft | 28 tiles |
Factoring in Grout Lines
Does grout size affect how many tiles you need? Yes. Grout takes up physical space on your floor. If you use a wide 1/4-inch grout line across a large room, it essentially acts as extra square footage, meaning you need slightly fewer physical tiles.
Our calculator automatically adds the chosen grout width to the dimension of a single tile before dividing it into the room area. However, because you are still adding a 10% waste factor, the grout difference rarely changes the final number of boxes you actually need to buy.
Calculating Tiles for Complex Layouts
If you are using running bond layouts (like subway tile, where the joints are staggered), the mathematical area remains the same, but the number of cuts you have to make at the edges of the wall increases. Every time you cut a tile in half to start a staggered row, you lose the other half if it doesn’t fit the opposite wall perfectly.
For running bond, herringbone, or diagonal patterns, always bump your waste factor up to 15% in the calculator.
Tile Calculator Frequently Asked Questions
To find out how many tiles you need, multiply your project length by its width to find the total area. Calculate the area of a single tile (including the grout line), divide your project area by the tile area, and then add a 10% waste factor to ensure you have enough for cuts and breakages.
Calculate the total square footage of the room, divide it by the square footage of a single tile, and multiply the result by 1.10 (to add a standard 10% waste factor). Round up to the nearest whole box if buying in packages.
A standard 12×12 inch tile is exactly 1 square foot. To cover 100 square feet, you mathematically need 100 tiles. However, because you must account for cuts and breakages (a 10% waste factor), you should purchase 110 tiles.
Determine the area of a single tile in square meters by multiplying its length by its width in meters. Divide 1 by that tile area. For example, a 30cm x 30cm tile is 0.09 sqm. 1 ÷ 0.09 = 11.11 tiles per square meter.
Yes. Wide grout lines (e.g., 1/4 inch) take up physical space. Over a large floor, this can mean needing slightly fewer tiles overall. However, because you must still order 10% extra for waste, the grout difference rarely changes how many boxes you actually need to buy.
Reference: https://en.wikipedia.org/wiki/Paint