Tile Calculator

Tiling a 12 ft by 10 ft room - that's 120 square feet - with standard 12×12 inch tiles takes exactly 120 tiles to cover the floor, because each 12×12 tile spans one square foot. But you should not buy 120. Add the recommended 10% for waste and you'll want about 132 tiles, which is the number this tile calculator gives you. That cushion covers edge cuts, the inevitable cracked tile, and a few spares for repairs down the road. Buy too few and you risk a second trip - or worse, a batch that no longer matches.

The formula

Counting tiles is pure geometry. First convert your tile's footprint to square feet, then divide your area by it and add waste:

The 144 converts square inches to square feet (12 inches × 12 inches = 144 square inches in a square foot). A 12×24 inch tile, for example, covers (12 × 24) ÷ 144 = 2 sq ft each. Always round up to whole tiles - you can't buy a fraction - and round boxes up too.

Worked example with real numbers

Say you're tiling a kitchen floor that measures 15 ft by 12 ft with 12×24 inch large-format tiles, and you want a 15% waste allowance because you've chosen a diagonal layout:

• Area: 15 × 12 = 180 sq ft
• Single-tile area: (12 × 24) ÷ 144 = 2 sq ft per tile
• Tiles to cover: 180 ÷ 2 = 90 tiles
• With 15% waste: 90 × 1.15 = 103.5 → round up to 104 tiles
• Boxes (6 tiles/box): 104 ÷ 6 = 17.3 → round up to 18 boxes

So you'd order 18 boxes - 108 tiles - covering 216 sq ft. The extra above 104 is normal slack from buying whole boxes, and it gives you handy spares.

How to measure your space

An accurate count starts with an accurate measurement. Work room by room:

1. Measure length and width of the room at the floor in feet. Measure to the longest points and round up to the nearest inch or tenth of a foot.
2. Multiply length × width to get square feet. For a 12.5 ft by 9 ft room that's 112.5 sq ft.
3. Split irregular rooms into rectangles. For an L-shape, measure each rectangular section separately and add the square footage together.
4. For walls, use height × width instead, and subtract large openings such as windows, mirrors, or a vanity if they're sizable.
5. Don't deduct small obstacles like a toilet flange or a single cabinet - the waste allowance covers those, and you'll cut tiles to fit anyway.

How to use this calculator

Enter your numbers and read the result instantly:

1. Choose Length × width and type the room dimensions in feet, or switch to Total sq ft if you already know the area.
2. Enter your tile size in inches (width and height), or tap a preset like 12×12 or 12×24.
3. Set the waste percentage - 10% is the default for a straight layout; bump it to 15-20% for diagonal or herringbone.
4. Optionally enter tiles per box from the product listing to get a box count.
5. Press Calculate tiles to see the total to buy, the extra for waste, and the number of boxes.

Who this calculator is for

• DIY homeowners tiling a bathroom floor, kitchen backsplash, or laundry room over a weekend.
• First-time tilers who want a confident shopping list before heading to the store.
• Renovators budgeting a project and needing a quick material count for an estimate.
• Anyone comparing tile sizes - switch the dimensions to see how 12×12 vs 12×24 changes the count.

Key terms explained

• Square foot (sq ft): the standard US unit of area, equal to a 12×12 inch square. Floors and tile coverage are measured in square feet.
• Single-tile coverage: how much area one tile covers, in square feet. It's the tile's width times height in inches, divided by 144.
• Waste factor (overage): the percentage added to your bare coverage to cover cuts, breakage, and spares - typically 10% for straight layouts.
• Large-format tile: any tile with a side of 15 inches or more (like 12×24 or 24×24). Fewer grout lines, but more cutting at edges.
• Box coverage: the total square footage one box of tiles covers, printed on the label alongside the tiles-per-box count.
• Lot / batch number: a code on each box. Tiles from the same lot share a shade; different lots can vary, which is why ordering enough up front matters.

Three quick scenarios

Here's how the count changes for the same 100 sq ft floor depending on tile size and layout (10% waste unless noted):

• 12×12 tiles, straight: 1 sq ft each → 100 to cover → about 110 tiles to buy.
• 6×6 tiles, straight: 0.25 sq ft each → 400 to cover → about 440 tiles - small tiles mean many more pieces.
• 12×24 tiles, herringbone (20% waste): 2 sq ft each → 50 to cover → about 60 tiles - the angled pattern drives the higher overage.

What changes the result the most

• Area: the biggest driver - measure carefully, since an error here scales straight through to the tile count.
• Tile size: smaller tiles cover less each, so you need far more of them for the same floor.
• Layout pattern: diagonal and herringbone need more waste because perimeter cuts are larger and more frequent.
• Room complexity: lots of corners, niches, and angled walls mean more cuts - lean toward the higher waste figure.

Tips for a smooth tile project

• Always order about 10% extra (15-20% for angled patterns) and keep the leftovers - matching tile years later is hard.
• Buy from one lot number so every box is the same shade; check the label before you leave the store.
• Dry-lay a row before setting anything to plan where cuts fall and avoid thin slivers at the walls.
• Round up to whole boxes - you can usually return unopened ones, but you can't run out mid-job.
• Don't forget the extras: thinset, grout, spacers, and trim are separate purchases this calculator doesn't size.

Limitations and assumptions

This is a planning estimate, not an exact installation plan. Keep these in mind:

• It assumes a flat, rectangular surface. For irregular shapes, split the area into rectangles and add them.
• It does not subtract grout lines, since the waste allowance more than covers that small gap.
• It does not size grout, adhesive, trim, or underlayment - those are separate calculations.
• The waste percentage is a guideline; complex rooms and intricate patterns may need more than the defaults.
• Box counts depend on the tiles-per-box you enter - always confirm the figure on the actual product label.

Tile types and materials

The calculator counts pieces the same way no matter what the tile is made of, but the material you choose affects how much waste you should plan for, how the tiles cut, and how many crack on the way in:

• Ceramic: the budget-friendly all-rounder. Soft enough to score-and-snap with a manual cutter, so cuts are clean and breakage is low - the standard 10% waste is usually plenty for a straight layout.
• Porcelain: denser and harder than ceramic, water-resistant, and common in large-format sizes. It needs a wet saw to cut and chips more easily at the edges, so lean toward the higher end of your waste range.
• Natural stone (marble, travertine, slate): beautiful but variable. Shade and veining differ piece to piece, edges chip, and some slabs arrive cracked, so many installers add 15-20% even for a straight layout and hand-pick tiles as they go.
• Glass and mosaic: usually sold on mesh-backed sheets rather than loose tiles. Calculate by the sheet's coverage rather than per piece, and add extra for the cuts you make through the mesh at corners and edges.
• Large-format (15 in or larger on a side): fewer grout lines and a cleaner look, but a single cracked tile wastes a lot of square footage, and an out-of-flat subfloor shows badly. Buy a couple of spares beyond your waste percentage.

Whatever the material, the count comes from the same area-divided-by-coverage math - the tile type only nudges the waste percentage you should enter.

Tile vs. other floor coverings

Tile is sold and estimated by area plus waste, and so are most other hard surfaces - which is why the same measuring step feeds several tools. If you are still choosing a surface, it helps to compare how each one is counted:

• Tile is counted in whole pieces and boxes, with 10-20% waste depending on the layout pattern. Edge cuts and breakage drive the overage.
• Sheet vinyl, laminate, and engineered wood are sold by the carton covering a set square footage, much like tile boxes. The Flooring Calculator handles planks and sheet goods with their own waste guidance.
• Carpet comes on 12-foot-wide rolls and is bought by the square yard, so seams and roll width - not tile cuts - decide the waste.
• Paint for the same room's walls is estimated by coverage per gallon rather than per piece; the Paint Calculator sizes that side of a remodel.

In every case the first step is the same: get an accurate square footage. Measure once with the Square Footage Calculator and you can reuse that number across the tile, flooring, and paint estimates for the whole room.

Budgeting the rest of the job

Tile itself is only one line on the materials list. A realistic budget also covers the things this calculator deliberately leaves out, because skipping them is what blows a remodel over budget:

• Thinset / mortar: the adhesive bed under the tile, sold by the bag with a coverage figure that depends on tile size and trowel notch. Large-format tiles need more.
• Grout: sized from the joint width, tile size, and area - the wider the grout line and the smaller the tile, the more you need.
• Backer board or underlayment: the substrate that keeps the floor flat and waterproof in wet areas. For a poured base, footing, or mortar bed, the Concrete Calculator and Cubic Yard Calculator handle the volume.
• Trim and transitions: bullnose, edge profiles, thresholds, and reducer strips at doorways - bought by the linear foot, not the square foot.
• Spacers, sealer, and tools: small but real, especially for a first-time job.

For outdoor work, a patio or paver base is estimated by volume rather than by piece - the Gravel Calculator sizes the crushed-stone bed, and the Mulch Calculator covers the surrounding landscaping. Add these to your tile count and you have a complete shopping list rather than a surprise second trip.

Sources and method

The count comes from the standard coverage formula every tile setter uses - total area divided by the area one tile covers, rounded up to whole tiles, plus a waste allowance for cuts and breakage. The unit conversion (144 square inches per square foot) and the waste ranges are industry conventions rather than legal standards, so treat the result as a well-grounded shopping estimate and confirm the box coverage on your actual product label.

• Area ÷ single-tile coverage, rounded up to whole tiles - the geometric basis used across tile-industry installation guidance.
• Waste allowance: about 10% for a straight grid, 15% for diagonal, and 15-20% for herringbone and other angled patterns, reflecting how much more perimeter cutting each layout requires.
• Tiles per box and box coverage come from the manufacturer's product label, which you enter into the calculator.