Tile Calculator
A 10 by 12 ft room needs 132 tiles when you use 12 by 12 in tile with 10% waste. That sounds simple, but real tile jobs get messy fast. Doorways steal full pieces. Diagonal layouts create more cuts. Showers and backsplashes add outlets, niches, and edges that increase breakage and offcuts. This tile calculator starts with the core math you actually need for ordering. Enter the installation width and length in feet, enter the tile size in inches, choose a waste percentage, and the tool returns the estimated tile count, area, and coverage per tile so you can sanity check the order before you buy.
Quick answer
The calculator finds the installation area in square feet by multiplying width by length.
What this tells you
- •The calculator finds the installation area in square feet by multiplying width by length.
- •It converts one tile from inches to square feet so the tile area matches the room area.
- •It divides area by tile area, applies waste for cuts and breakage, and rounds up because tile is bought as whole pieces.
How to Use
- 1Measure the longest width and length of the tile area in feet. For a simple floor, that is usually wall to wall. For a shower wall or backsplash, measure only the section that actually receives tile.
- 2Enter the tile width and tile length in inches. A 12 by 24 tile covers twice the area of a 12 by 12 tile, so size matters as much as room dimensions.
- 3Set the waste percentage based on the layout. About 10% works for many straight set jobs. Diagonal patterns, narrow rooms, herringbone layouts, and walls with many cutouts often need 12% to 15% or more.
- 4Click Calculate to see the tile count. Use the area and tile area results to double check that the numbers pass a quick smell test before ordering.
How It Works
Formula
Area ft2 = Width ft x Length ft
Tile ft2 = (Tile Width in x Tile Length in) / 144
Tiles Needed = ceil((Area ft2 / Tile ft2) x (1 + Waste%))Width times length gives total area in square feet. Tile dimensions are entered in inches, so the calculator converts each tile to square feet by dividing by 144. It then divides the project area by one tile's coverage, adds waste, and rounds up to a whole tile because you cannot order 131.2 tiles.
Calculation note: values are processed in the order shown above, using the current input units.
Worked Examples
Kitchen floor with standard 12 by 12 tile
The floor area is 10 x 12 = 120 sq ft. Each 12 x 12 in tile covers 1 sq ft. The base count is 120 tiles, and adding 10% waste brings the order to 132 tiles.
Bathroom floor with large format 12 by 24 tile
The floor area is 80 sq ft. A 12 x 24 in tile covers 2 sq ft, so the raw count is 40 tiles. A 12% waste factor raises the order to 44.8, which rounds up to 45 tiles. That extra margin helps when the layout starts with a centered pattern or when walls are not perfectly square.
Backsplash with small subway tile
A long backsplash at 15 ft by 1.5 ft covers 22.5 sq ft. One 3 x 6 in subway tile covers 0.125 sq ft, so the base count is 180 tiles. A 15% waste factor raises that to 207 tiles, which is realistic once you account for outlet cuts, end cuts, and matching the layout under cabinets.
Typical Waste Allowances for Tile Layouts
Use these as planning defaults when you do not already know the exact pattern and cut complexity. Cleaner layouts usually waste less. Tight rooms, diagonal work, and feature layouts waste more.
| Project type | Common waste | Why it changes |
|---|---|---|
| Straight lay floor in a simple room | 8% to 10% | Mostly perimeter cuts |
| Large format floor tile | 10% to 12% | Bigger tiles often mean bigger offcuts |
| Diagonal floor layout | 12% to 15% | Every wall edge creates angled cuts |
| Backsplash with outlets | 12% to 15% | Receptacles and ends interrupt the pattern |
| Herringbone or intricate pattern | 15% to 20% | More cuts and less reusable scrap |
If the tile has noticeable shade variation or a limited dye lot, ordering a little extra at the start is safer than trying to match material later.
What This Tile Estimate Assumes
This calculator assumes the full measured width and length receive tile and that every tile in the field is the same nominal size. It treats the job as one simple rectangle, which is the right starting point for ordering but not the final layout plan. If your room has a tub deck, kitchen island, closet notch, bench, or stair return, measure those sections separately and add or subtract area before you buy.
It also assumes your waste setting covers the real job conditions. That is the big judgment call. A straight grid on a square laundry room wastes less than a diagonal porcelain floor in a hallway that pinches down at one end. The math is identical. The offcuts are not. If you know the space is awkward, trust that and raise the waste percentage instead of pretending the room is friendlier than it is.
Tile is also sold in boxes, not loose pieces, in many stores. If your result says 132 tiles and the product comes 10 pieces per box, you still need to round up to full cartons when you place the order. Use this calculator to get the piece count first, then compare that number with the box coverage or carton quantity on the product sheet.
Common mistakes
- Using the outside room dimensions even when cabinets, islands, tubs, or vanities reduce the actual tile area
- Keeping waste at 10% for a diagonal, herringbone, or cut-heavy layout that clearly needs more margin
- Mixing feet for the room and inches for the tile without converting units, which can blow up the tile count
- Ordering the exact piece count without checking how many tiles or square feet come in a full box
- Forgetting to keep spare attic stock for future repairs when the tile may be discontinued later
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