How many tiles do I need?
The area of one tile in square feet = its width x its height in inches / 144, because a square foot is 12 x 12 = 144 square inches. [1] Tiles = the area to tile x (1 + the extra) / the area of one tile, rounded up.
Worked example
An area 10 ft long and 10 ft wide is 10 x 10 = 100 square feet. One tile 12 in by 12 in is 12 x 12 / 144 = 1.00 square foot, so 100 / 1 = 100 tiles as measured. With an example extra of 10%, 100 x 1.1 = 110 square feet, and 110 / 1 = 110 tiles.
How much extra tile should I order?
Clay Imports, a tile seller, recommends ordering 15-20% overage to account for cuts, natural variation and future repairs, and recommends retaining surplus tiles from your original order. [2]
Flooring Clarity lists 10% for a simple layout, 15% for a complex layout and 20% for a diagonal or patterned layout of ceramic and porcelain tile. [3]
The two sources do not agree and neither is a standard, so Extra to order starts at 10 as an example. Enter the extra your installer or tile maker gives you.
| Layout | Extra (%) | Tiles |
|---|---|---|
| Simple layout | 10 | 110 |
| Complex layout | 15 | 115 |
| Diagonal or patterned layout | 20 | 120 |
How many tiles for 100 square feet?
Tiles per 100 square feet for four example sizes, as measured and with an example extra of 10%. The sizes are examples to show the sum.
| Tile size (in) | Area of one tile (ft²) | Tiles as measured | Tiles with 10% extra |
|---|---|---|---|
| 6 x 6 | 0.25 | 400 | 440 |
| 12 x 12 | 1 | 100 | 110 |
| 12 x 24 | 2 | 50 | 55 |
| 24 x 24 | 4 | 25 | 28 |
Tile for a floor, wall, shower, backsplash or ceiling
The sum is the same for every surface: find the area, take away what is not tiled, and divide by the area of one tile. For a wall, shower or backsplash, measure the height and the width of each wall and add the areas. Enter a tub, a vanity or a window under Area not to be tiled.
How many tiles for a bathroom floor?
A floor 5 ft by 8 ft is 40 square feet. With 12 x 12 in tiles that is 40 tiles as measured, and 44 with an example extra of 10%.
How much grout do I need?
We found no source for grout coverage, so this calculator does not count grout. Read the coverage on the bag, which depends on the grout and the joint.
How much thinset do I need?
We found no source for thinset coverage, so this calculator does not count it either. The coverage is printed on the bag and depends on the trowel your tile needs.
How much does tile cost?
We state no price. Ask local sellers for the price of one tile, then enter it under Price per tile, in the section Tiles per box and price (optional) above, to see the total. The site does not store the prices you type.
Common mistakes and limits
- Mixing units. Enter the length and width in feet and the tile size in inches.
- Buying from different batches. Clay Imports says it cannot guarantee an exact match in color, sheen, shade, thickness or sizing between separate production batches. [2]
- Forgetting the boxes. Enter the tiles in one box, printed on it, and the calculator rounds up to whole boxes.
- What this tool does not cover: grout, thinset, spacers, trim tiles and the layout of the cuts.
Frequently asked questions
How many boxes of tile do I need?
Open Tiles per box and price (optional) and enter the number of tiles in one box, printed on it. The calculator divides the tiles to order by it and rounds up.
Should all the tile come from one batch?
Clay Imports says it cannot guarantee an exact match in color, sheen, shade, thickness or sizing between separate production batches, and recommends retaining surplus tiles from the original order. [2]
How much extra for a diagonal layout?
Flooring Clarity lists 10% for a simple layout, 15% for a complex one and 20% for a diagonal or patterned layout of ceramic and porcelain tile. [3]
How many tiles are in a square foot?
144 divided by the area of one tile in square inches: 4 tiles of 6 x 6 in, 1 tile of 12 x 12 in, or half a tile of 12 x 24 in. [1]
How much does it cost to tile a small bathroom?
We state no price. Ask local sellers for the price of one tile or one box, then enter it under Tiles per box and price (optional) above to see the total for the tiles to order.
Sources and references
- National Institute of Standards and Technology (NIST). NIST Guide to the SI, Appendix B.8: Factors for Units Listed Alphabetically (SP 811, accessed November 2026). Used for: the inch and foot relationship (144 square inches in a square foot).
- Clay Imports. Should I order any overage or extra material? How much? (accessed November 2026). Used for: one tile seller's advice on extra tile, and keeping spares.
- Flooring Clarity. How Much Extra Flooring To Buy (2025, accessed November 2026). Used for: one flooring site's extra for ceramic and porcelain tile by layout.
How we use sources: methodology.
Estimates only. Confirm quantities with your supplier. See the disclaimer. Found a wrong result? Report an error.