Tile Calculator
Tile math goes wrong at the units more than anywhere else: the room is measured in feet, the tile is sold in inches, and every estimate has to cross between them without dropping a factor of 144. This calculator does the conversion explicitly — tile footprint from its inch dimensions, room area from its feet — then applies the pattern-based waste the trade uses: 10% for a straight lay, 15% for diagonal, 20% for herringbone, because angled cuts sacrifice far more material. The result is a whole number of tiles and, since tile also ships by the box, a whole number of boxes. The chips at the top cover the common sizes from 2-inch mosaics to 12×24 planks, and the note that matters most is the one competitors skip: grout line width changes the layout, not the count — an 8-inch tile is 0.44 sq ft regardless of how wide the joints are.
The short answer
Tiles are counted in pieces: a 12×12 floor is 144 sq ft, a 12-inch square tile is 1 sq ft, so 144 tiles — plus 10% straight-lay waste is about 159 tiles, or 16 boxes at 10 per box. Diagonal patterns need 15% waste, herringbone 20%; an 8-inch tile covers only 0.44 sq ft each, which is where unit confusion doubles orders.
Blank = the pattern preset. Tiles you must not break: order spare.
On the box label — large-format tile often ships 6-8 per box.
Boxes to buy
16
159 tiles at 1 sq ft each, 10 per box.
- Tiles to buy
- 159
- Area to cover
- 144 sq ft
158.4 sq ft with 10% straight-lay waste ÷ 1 sq ft per tile — rounded up to whole pieces.
Before waste. Grout lines don't change the count — layout does: diagonal and herringbone patterns cut far more offcuts.
How to use Tile Calculator
- 1
Measure the floor
Length and width in feet. For an L-shape, split into rectangles and add the results.
- 2
Enter the tile size
Length and width in inches, straight off the product page — or tap a chip for a common size. The calculator converts to square feet per tile for you.
- 3
Pick the pattern and buy boxes
Straight lay at 10% waste is the default; diagonal is 15%, herringbone 20%. Pieces per box is on the label — large-format tiles often ship 6-8 per box.
Why use this tool
- Piece-level math with the inch-to-foot conversion done explicitly
- Pattern-based waste presets: 10% straight, 15% diagonal, 20% herringbone
- Whole-boxes answer from the pieces-per-box figure on the label
- Size chips for common tiles from mosaics to 12×24 planks
- Waste override for showers, alcoves and irregular floors
- Private — room dimensions never leave the browser
Frequently asked questions
- How many 12x12 tiles do I need for a 12x12 room?
- 144 tiles for the area, but order about 159: one square foot per tile on a 144 sq ft floor, plus the 10% straight-lay waste, rounded up to whole pieces. At 10 tiles per box that is 16 boxes. Diagonal layout: about 166 tiles; herringbone: about 173.
- How do I convert tile inches to square feet?
- Multiply the tile's length by its width in inches, divide by 144. A 12×12 tile is 144 ÷ 144 = 1 sq ft; an 8×8 tile is 64 ÷ 144 = 0.44 sq ft; a 3×6 subway tile is 18 ÷ 144 = 0.125 sq ft — meaning an 8 sq ft wall of subway tile takes 64 pieces, not 8. This step is where most DIY tile orders go wrong.
- What waste factor should I use for tile?
- 10% for a straight lay, 15% for diagonal, 20% for herringbone — angled cuts sacrifice more material per row. Add margin for showers with niches, rooms with many corners, and any tile laid on a diagonal across an irregular floor. Broken tiles in the box are the reason the waste factor exists at all.
- Does grout line width change how many tiles I need?
- Not meaningfully. Grout lines change the layout grid — a ⅛-inch joint versus a ¼-inch joint shifts where cuts land — but the tile count is driven by area, and the joints' share of area is small. The count changes when the tile size changes, not when the joint does.
- How many tiles are in a box?
- It depends entirely on the product: 12×12 ceramic commonly ships 10-12 per box, large-format 12×24 planks 6-8, mosaics by the sheet. The label always states coverage per box — compare that to your area with waste, and round up to the whole box.
- Should I order extra tile beyond the waste factor?
- Yes, if the tile might be discontinued — and many are, within a few seasons. A spare box stored in the garage is the cheapest insurance in home renovation: dye lots shift, styles rotate, and a cracked tile in year five needs a matching piece that may no longer exist. Five years from now, you will not find this exact white 8×8 again.
- Is this right for wall tile and showers?
- The math is the same — wall area in sq ft, tile size, pattern waste — but showers add cuts around niches, valves and benches, so push the waste override to 15-20% even on a straight lay. Measure each wall separately and add them; a three-walled shower is not one flat rectangle.
How many boxes of flooring do I need? Room area with layout-based waste — 10% straight, 15% diagonal, 20% herringbone — rounded up to whole boxes, with cost.
How much paint do I need? Enter room size and openings for gallons at two-coat math — doors and windows deducted, Sherwin-Williams coverage, gallon + quart buying.
Concrete calculator for slabs, footings and columns: cubic yards with waste allowance, 80/60/40 lb bag counts, and when to order ready-mix instead.