Tile Square Footage Calculator
Buying tile comes down to two numbers: the area you're covering and the extra you order to cover cuts and breakage. Get the first wrong and your layout is off. Skip the second and you're back at the store hoping the dye lot still matches. This calculator handles the area, adds a waste factor that fits your pattern, and turns it into boxes so you know exactly what to put in the cart.
Step one: measure the area
Measure the surface in feet, length times width, and add up every section. For a rectangular floor that's one multiplication. A 10 by 12 bathroom floor is 120 square feet. For an L-shaped room or a floor interrupted by a vanity or an island, break it into rectangles, calculate each, and add them together. The pillar guide on calculating square footage walks through that rectangle-splitting method in detail.
Subtract large permanent fixtures you won't tile under, like a kitchen island base or a built-in tub. Don't bother subtracting a toilet flange or a floor drain. Those are small, and you want the tile to run under and around them cleanly.
If your measurements come out in inches, convert before you calculate. Divide square inches by 144 to get square feet, which is what our square inches to square feet converter does automatically.
Step two: add a waste factor
This is where people underbuy. Waste covers the tiles you cut to fit against walls, the ones that crack during scoring, the occasional factory dud, and the pieces you keep as attic stock for future repairs. The pattern you choose drives how much you need.
- Straight grid, standard sizes: 10 percent is the industry default. A simple stack or offset on a square room wastes very little.
- Diagonal (45 degrees): 15 percent. Turning the grid means every tile along the perimeter gets cut on an angle, and the offcuts usually can't be reused.
- Herringbone and chevron: 15 to 20 percent. These patterns cut a lot of tile, especially at the borders, and the geometry leaves awkward triangles you throw away.
- Small, busy, or heavily obstructed rooms: add a couple points. A tiny bathroom with a lot of edges relative to its area wastes proportionally more than a big open floor.
In a long thread on Tilers Forums about how many tiles to order for wastage, the consensus lands on 10 percent as the go-to number, with the note that a brick-bond or plank layout wastes more than a random bond because you can't always reuse the end cut to start the next row. Several tilers make the same practical point: relative to the total cost of the job, ordering the extra 10 percent is a no-brainer, and it saves you from a discontinued dye lot down the road.
Buy a little more than the math says and keep the leftovers. Tile lines get discontinued constantly, and a boxed spare from the original run is worth more than a close-enough replacement two years later.
Step three: convert tile size to coverage
You measured in square feet, but tile is sold by the piece and the box, and named by its nominal size in inches. Converting is quick once you know the coverage of a single tile.
- A 12 by 12 tile covers exactly 1 square foot. Tiles needed equals square feet.
- A 12 by 24 tile covers 2 square feet. Divide square feet by 2 for the piece count.
- A 6 by 24 plank covers 1 square foot. Same count as a 12 by 12.
- A 6 by 6 tile covers 0.25 square feet, so you need four per square foot.
- A 4 by 4 tile covers about 0.111 square feet, roughly nine per square foot.
- A 3 by 6 subway tile covers 0.125 square feet, eight per square foot.
The general formula: multiply the two tile dimensions in inches, then divide by 144 to get square feet per tile. A 12 by 24 is 288 square inches divided by 144, which is 2 square feet. Divide your total area (with waste) by that number to get the piece count.
Step four: buy by the box
Tile ships in boxes, and coverage per box varies by size and product. A box of 12 by 24 porcelain might hold 8 pieces for 16 square feet. A box of small mosaic sheets might cover 10 square feet. The box label always lists the square footage it covers, and that's the number you divide into your total. Always round boxes up. You can't buy two-thirds of a box, and the fraction becomes your spare.
Floor tile vs wall tile
They're calculated the same way, area times a waste factor, but they're not interchangeable products. Floor tile is rated for foot traffic and has a slip rating; wall tile is often thinner and lighter and can crack underfoot. If you're tiling a shower, measure the walls and the floor separately, because you'll likely use a smaller mosaic on the shower pan for slope and slip resistance and a larger tile on the walls. Add each surface's waste factor on its own rather than lumping them together.
Worked example: a diagonal kitchen floor
Say you're tiling a 12 by 14 kitchen on the diagonal with 12 by 24 porcelain, minus a 3 by 5 island you won't tile under.
- Room area: 12 ft x 14 ft = 168 sq ft.
- Subtract the island: 3 ft x 5 ft = 15 sq ft. So 168 - 15 = 153 sq ft.
- Add 15 percent for the diagonal pattern: 153 x 1.15 = 175.95, round to 176 sq ft.
- Convert to pieces: each 12 by 24 covers 2 sq ft, so 176 / 2 = 88 tiles.
- Buy by the box: if a box covers 16 sq ft, 176 / 16 = 11 boxes exactly. If a box covers 15.5 sq ft, that's 11.35 boxes, so buy 12.
Order the 12 boxes, tile the floor, and keep the leftovers labeled with the color and lot number in the garage.
Common mistakes
Using nominal size as actual size. A "12 by 12" tile is usually a hair under 12 inches to allow for the grout joint. It still covers a nominal square foot for ordering purposes, so calculate with the nominal size, not a tape measurement of the bare tile.
Ordering exact and hoping. Running out mid-install means a second order, a possible dye-lot mismatch, and downtime while it ships. The waste factor exists to prevent exactly this.
Forgetting the walls in a shower. People measure the pan and forget the three walls climb 6 or 7 feet. Measure every surface.
Frequently asked questions
How much tile do I need?
Measure the area in square feet, add a waste factor of 10 percent for a straight layout or 15 to 20 percent for diagonal or herringbone, then divide by the square footage each tile or box covers. For a 120 square foot floor with a straight grid, you'd order about 132 square feet of tile and round up to full boxes.
How do I calculate square footage for tile?
Multiply length by width in feet for each section of the surface and add the sections together. Subtract large fixtures you won't tile under. Then add your waste factor. If you measured in inches, divide square inches by 144 to convert to square feet first.
What waste factor should I use for tile?
Ten percent is standard for straight, square layouts. Bump it to 15 percent for a diagonal install and 15 to 20 percent for herringbone or chevron, since angled patterns cut more tile at the borders. Add a couple extra points for small rooms with lots of edges.
How do I convert tile size to coverage?
Multiply the tile's two dimensions in inches and divide by 144 to get square feet per tile. A 12 by 12 is 1 square foot, a 12 by 24 is 2 square feet, and a 4 by 4 is about 0.11 square feet. Divide your total area by that figure to get the piece count.
Should I buy extra tile for repairs?
Yes. Tile lines get discontinued and dye lots shift between production runs, so the waste factor you buy for cuts doubles as future repair stock. Keep at least a few boxed spares labeled with the color name and lot number.
Related tools
For the flooring side of a project, see the flooring square footage calculator, and for a single space use the room square footage calculator.
For any other shape or a whole project at once, start from the main square footage calculator.