Tile Calculator
Find how many tiles to buy for a floor, wall, backsplash, or shower. Enter the area to tile, the size of your tile, and the grout joint, and add the tiles per box to see how many boxes to buy. For planks or laminate, use the Flooring Calculator.
Add floors or walls, or subtract areas that need no tile, such as a window or a tub.
- Choose US or Metric. You can still change the unit of any single field.
- Enter the area to tile. For a floor, enter the room's length and width. For a wall, enter the wall's length as Length and its height as Width. Use Add section for more areas, and set a section to Subtract for a window, a door, or a tub.
- Enter the Tile length and Tile width. Use the actual size printed on the box or product page.
- Check the Grout joint. It starts at 1/8 in (3 mm). Change it to match your tile and the manufacturer's instructions.
- Choose the Layout. It sets the waste allowance: 10% for a straight layout and 15% for diagonal or herringbone.
- Optionally, enter the Tiles per box to see how many boxes to buy, and a price per square foot, square yard, square meter, tile, or box to estimate the cost.
For mosaic tiles on sheets, enter the size of one sheet as the tile size
and the joint between sheets as the grout joint. Dimension fields accept
whole numbers, decimals, fractions, and mixed numbers, such as
12, 11.75, 3/16, or
23 3/4.
How many tiles you need
The calculator finds the area to tile, adds the waste allowance, and divides by the area of one tile plus its share of the grout joints:
Total area = net area × (1 + waste % ÷ 100)
Tiles = total area ÷ ((tile length + joint) × (tile width + joint)), rounded up
Boxes = tiles ÷ tiles per box, rounded up
Each tile shares the joints around it with its neighbors, so each tile takes up one joint width in each direction. Convert every measurement to the same unit before you divide. With several sections, the calculator adds the sections set to Add and subtracts those set to Subtract. For shapes other than rectangles, it uses these formulas:
| Shape | Area |
|---|---|
| Rectangle | length × width |
| Circle | π × diameter² ÷ 4 (or π × radius²) |
| Triangle (base and height) | base × height ÷ 2 |
| Triangle (three sides) | Heron's formula: √(s(s − a)(s − b)(s − c)), where s = (a + b + c) ÷ 2 |
| Trapezoid | (parallel side A + parallel side B) ÷ 2 × height |
| Ring | π × (outer diameter² − inner diameter²) ÷ 4 |
| Rectangular border | outer length × outer width − (outer length − 2 × border width) × (outer width − 2 × border width) |
| Known area | the area you enter |
How much extra tile to buy
Cutting tiles to fit the edges leaves offcuts, and layouts at an angle leave more. The calculator starts from these allowances:
| Layout | Waste allowance |
|---|---|
| Straight A grid or offset rows, such as a subway or brick pattern | 10% |
| Diagonal Tiles at 45° to the walls | 15% |
| Herringbone or chevron Rectangular tiles meeting at an angle in a zigzag pattern | 15% |
- The US tile supplier Best Tile says a typical waste factor is about 10%, and recommends 15% for tile laid diagonally or for a room with many jogs and corners.
- The tile maker Clé Tile recommends ordering 10% more tile than your measurements, and more for complex patterns and diagonal layouts.
Small rooms, rooms with many corners, and large tiles need a larger allowance than large, simple rooms. Change the waste allowance to match your project.
Tile size and grout joints
Tiles sold as 12 in × 24 in are often slightly smaller. For example, Ivy Hill Tile's 12 in × 24 in porcelain comes 8 tiles to a box covering 15.75 sq ft, or 1.97 sq ft per tile rather than 2. Use the actual size printed on the box, or the number of tiles will come out low.
Custom Building Products' technical bulletin on grout joint width says that the TCNA recommends a joint of at least 1/8 in for rectified tile and 3/16 in for calibrated tile, and that a joint should never be less than 1/16 in (1.6 mm). The UK's Tile Association says floor joints should be at least 3 mm wide, and allows joints as narrow as 2 mm for wall tiles smaller than 0.1 m². Change the joint to match your tile and where it goes, following the joint width recommended for your tile.
How many tiles come in a box
The number of tiles in a box depends on the tile size and the product, so it varies even between tiles of the same size. Some examples:
| Product | One box |
|---|---|
| Ivy Hill Tile 12 in × 24 in porcelain (US) | 8 tiles, 15.75 sq ft |
| Daltile Restore 3 in × 6 in subway tile (US) | 12.5 sq ft |
| Lily Bain 600 mm × 600 mm porcelain (UK) | 3 tiles, 1.08 m² |
These are only examples. Check the number of tiles printed on the box or the product page of the tile you buy, and enter it as the Tiles per box.
Examples
A bathroom floor
A floor 10 ft × 8 ft is 80 ft². With a 10% waste allowance, the total is 88 ft². A 12 in × 12 in tile with a 1/8 in joint takes up 12.125 × 12.125 = 147.02 in², or 1.021 ft², so 88 ÷ 1.021 = 86.19, and you need 87 tiles. With 10 tiles per box, buy 9 boxes.
A kitchen backsplash
A backsplash 10 ft long and 18 in high is 15 ft², or 16.5 ft² with 10% added. With 3 in × 6 in subway tiles and a 1/16 in joint, you need 128 tiles.
A shower with three walls
A shower has a back wall 5 ft wide and two side walls 32 in wide, all 8 ft high. Enter the back wall as one section, and the side walls as a second section with a Quantity of 2. For the 32 in, set the unit to in, or enter 2 ft 8 in with ft + in.
The walls add up to 40 + 42.67 = 82.67 ft², or 90.93 ft² with 10% added. A 12 in × 24 in tile with a 1/8 in joint takes up 12.125 × 24.125 = 292.52 in², or 2.031 ft², so 90.93 ÷ 2.031 = 44.77, and you need 45 tiles. With 8 tiles per box, buy 6 boxes. The floor usually takes a different tile, so calculate it separately.
Metric dimensions
A floor 3 m × 2.5 m is 7.5 m², or 8.25 m² with 10% added. With 600 mm × 300 mm tiles and a 3 mm joint, you need 46 tiles. With 6 tiles per box, buy 8 boxes.
FAQ
It depends on the tile size. With a 1/8 in grout joint and before waste, you need about 0.98 tiles per square foot for 12 in × 12 in tiles, 3.8 for 6 in × 6 in tiles, and 7.5 for 3 in × 6 in subway tiles. Round the total for your area up to a whole tile.
With a 3 mm grout joint and before waste, you need about 2.75 tiles per square meter for 600 mm × 600 mm tiles, 5.5 for 600 mm × 300 mm tiles, and 10.9 for 300 mm × 300 mm tiles. Round the total for your area up to a whole tile.
About 10% for a straight layout and 15% for a diagonal or herringbone layout. Add more for small rooms or rooms with many corners.
Related calculators
- Grout Calculator
How much tile grout to buy by weight, and how many bags, from the tile size and joint.
- Square Footage Calculator
Area in square feet, square yards, and square meters.
- Flooring Calculator
Flooring area including waste for your layout, and how many boxes to buy.
- Paver Calculator
How many pavers to buy for a patio or driveway, with the bedding sand and base.
- Carpet Calculator
How much carpet to buy from a roll for a room, with the seams, and the cost with pad and installation.
- Paint Calculator
How much paint to buy for walls and ceilings, in gallons or liters.