Tile Calculator: How Many Tiles Do I Need?
Tile is fragile, unforgiving and expensive to reorder — a second batch may not even match the first. This free tile calculator tells you exactly how many tiles to buy for any floor or wall: enter your total area, your tile dimensions in inches, and it adds the right waste allowance for cuts and breakage, then shows the tile count and estimated cost. Use it for bathroom floors, kitchen backsplashes, shower walls and entryways alike.
Tile Quantity Calculator
How to Use This Tile Calculator
First, find your total area to tile. For a floor, multiply the room's length by its width in feet. For a wall, multiply the wall's width by its height. For a shower or room with multiple surfaces, measure each surface separately, add them together, and enter the single total.
Next, enter your tile size in inches — 12 × 12 is the classic, but the tool handles any rectangular tile from tiny mosaics to 24 × 48 slabs. Set the waste allowance: 10% is right for a standard straight layout, 15% for diagonal layouts or large-format tile that breaks easily. Enter a price per tile if you want a cost estimate, then click Calculate.
The Tile Calculation Formula
A tile's coverage in square feet is (tile width × tile height) ÷ 144, because a square foot is 144 square inches. The number of tiles is area ÷ tile coverage × (1 + waste ÷ 100), rounded up to whole tiles.
Worked example: a 12 × 12 room is 144 square feet, and a 12 × 12-inch tile covers exactly 1 square foot. With 10% waste: 144 ÷ 1 × 1.10 = 158.4 — so you buy 159 tiles. Those 15 extra tiles are not a luxury: every edge row needs cutting, a few tiles will crack during the job, and keeping a handful of spares means a future repair uses the same batch and shade.
Pro Tips for Ordering Tile
Order everything at once and note the dye lot printed on each box. Tile color varies slightly between production batches, and even a subtle difference becomes obvious across a sunlit floor. For the same reason, keep 5 to 10 spare tiles after the job finishes.
Think about layout before you buy. Diagonal layouts waste more material but hide out-of-square walls; offset patterns suit rectangular tiles and busy households because they disguise imperfect joints. And check your substrate: floors need backer board or an uncoupling membrane, walls need the right adhesive weight for large tiles — a 24 × 24 tile weighs a lot, and the wrong mortar lets it slide right off the wall.
Frequently Asked Questions
How many tiles do I need for a 12x12 room?
A 12x12 room is 144 square feet. Using 12x12-inch tiles (1 square foot each) with a 10% waste allowance, you need 144 × 1.10 = 159 tiles. The extra 15 tiles cover cuts at the walls and breakage.
How much extra tile should I buy for waste?
Add 10% for a standard square layout, 15% for a diagonal layout or large-format tile, and up to 20% for intricate patterns or rooms with many corners and obstacles. Never order the exact measured area — cuts and breakage are unavoidable.
How many 12x12 tiles do I need per square foot?
Exactly one 12x12-inch tile per square foot (a 12x12 tile is 144 square inches, and a square foot is 144 square inches). Larger tiles cover more: a 24x24 tile covers 4 square feet.
How do I figure out tile for shower walls?
Measure each shower wall separately (width × height in feet), add the areas together, then add 15% waste — shower walls have cutouts, niches and lots of cuts. Use this calculator with the total area.
What tile size should I use for a small room?
Larger tiles, counterintuitively, make small rooms feel bigger - fewer grout lines mean less visual clutter. 12x24 tiles laid in a brick pattern are the current standard. Very small mosaics are best reserved for shower floors, where the extra grout lines add slip resistance.
How do I lay out tile for a backsplash?
Start from the most visible corner and center the pattern on the focal point (usually the range hood or window), so cut tiles fall at the ends. Mark a level line, dry-lay a row to check the cuts, and use a laser level or chalk line so courses stay straight.
Do large-format tiles need special mortar?
Yes - tiles 15 inches or larger on any side should use a large-format thinset, which is formulated to prevent sagging and lippage. Floor tiles of this size also want a level substrate (within 1/8 inch over 10 feet), or the edges will catch and crack.