Tile Calculator
Count the tiles, boxes and thinset needed for a floor or wall.
What you'll need to order
- tile
- thinset mortar
- grout
- tile spacers
- backer board
Prices vary by region and haul distance. Get quotes from at least two local suppliers.
How this calculator works
tiles = (area ÷ tile area) × 1.10
Tile area comes from length times width in inches divided by 144. Ten percent covers cuts on a straight lay; go to 15% for a diagonal layout and 20% for herringbone, where offcuts are rarely reusable.
Switch the site to metric — the control is in the footer — and your inputs, your results and the tables below follow. The formula, the constants, the guidance text and the sources stay in US units on purpose: that is how the standards they come from are written, and restating them would detach each figure from the document you are meant to be able to check it against.
Where these numbers come from
- ANSI A108/A118/A136 (Installation of Ceramic Tile) 2023 — installation tolerances; waste allowance by layout is a trade convention
Check the edition. Codes are amended every few years, and the one your inspector works from may not be the one named above.
Worked example
With area length 12 ft, area width 10 ft, tile length 12 in, tile width 12 in, this calculator returns 132 .
Waste allowance
The headline figure includes a 10% allowance for waste and over-ordering. The exact requirement is shown alongside it.
Tiles needed by tile size
Figures below assume area length 12 ft × area width 10 ft × tile width 12 in. Each row is a link that fills in the calculator above. Send one and the other end sees the same figures you do.
| Tile length | Tiles needed | Thinset bags (50 lb) (bags) |
|---|---|---|
| 4 in | 396.0 | 1.33 |
| 6 in | 264.0 | 1.33 |
| 8 in | 198.0 | 1.33 |
| 12 in | 132.0 | 1.33 |
| 18 in | 88.00 | 1.33 |
| 24 in | 66.00 | 1.33 |
| 36 in | 44.00 | 1.33 |
A 12 by 10 ft room with tiles 12 in wide. Larger tiles mean fewer pieces but less tolerance for an uneven floor.
Tile quantities for common rooms
Every row here opens the calculator already filled in. Copy that link and the numbers travel with it.
| Job | Size | Tiles needed |
|---|---|---|
| Small bathroom floor | 8 ft × 6 ft × 12 in × 12 in | 52.80 |
| Kitchen backsplash | 10 ft × 2 ft × 6 in × 3 in | 176.0 |
| Shower surround | 15 ft × 6 ft × 12 in × 24 in | 49.50 |
| Kitchen floor | 14 ft × 12 ft × 18 in × 18 in | 82.13 |
| Open-plan living area | 24 ft × 18 ft × 24 in × 24 in | 118.8 |
| Entry hall | 12 ft × 6 ft × 12 in × 12 in | 79.20 |
Counts are exact coverage before waste. Add 10% for a straight lay, 15% for diagonal and 20% for herringbone or a room with many angles.
What does tile cost per square foot?
Material typically runs $2 to $15 per square foot. Material only. Professional installation adds $5 to $14 per square foot depending on tile size, pattern and how much floor preparation is needed.
What moves the price:
- Material — ceramic is cheapest, porcelain mid-range, natural stone the most expensive
- Size: large-format tile costs more to buy and more to lay flat
- Pattern, since diagonal and herringbone add both waste and labour
- Substrate preparation, self-levelling compound and uncoupling membrane
Prices are US averages and move with fuel, season and haul distance. Always get two local quotes before budgeting.
Tile waste allowance by pattern
| Type | Extra to order (%) | Notes |
|---|---|---|
| Straight lay, square room | 10.00 | The standard allowance |
| Straight lay, many angles | 15.00 | More cuts means more offcuts |
| Diagonal | 15.00 | Every perimeter tile is cut |
| Herringbone or chevron | 20.00 | High waste at every edge |
| Large-format over 24 in | 15.00 | Breakage during handling is common |
Order the whole job from one batch. Dye lots differ visibly between production runs, and a repair two years later will never match unless you kept spares.
Frequently asked questions
How do I calculate how much tile I need?
Work out the area in square feet, divide by the area of one tile in square feet, then add 10 to 20% for waste. A 12x12 in tile is exactly one square foot, which makes that case easy.
How many 12x24 tiles in a box?
Typically six, covering about 12 square feet, though it varies by manufacturer. The coverage per box is always printed on the label — order against that figure, not the tile count.
What size trowel do I need for tile?
A 1/4 in square notch for tiles up to 12 in, 1/2 in for large format, and a 3/16 in V-notch for mosaic. Trowel size drives thinset consumption more than anything else.
Do I need backer board under tile?
On floors, cement backer board or an uncoupling membrane over plywood. In wet areas, a waterproof board is required. Tile laid directly on plywood will crack as the substrate moves.
How many 12x12 tiles do I need per square foot?
Exactly one, since a 12 by 12 inch tile covers one square foot. For 6 by 6 tiles it is four per square foot, and for 18 by 18 it is 0.44.
How much extra tile should I buy?
Ten percent for a straight lay, 15% for diagonal, 20% for herringbone. Buy it all in one order — tile is made in batches and the shade varies between them, so a later top-up will not match.
How much thinset do I need?
A 50 lb bag covers about 90 sq ft with a 1/4 inch square-notch trowel. Large-format tile needs a 1/2 inch notch, which halves coverage to roughly 45 sq ft per bag.
Should I keep spare tiles?
Keep at least a full box. Cracked tiles get replaced years later, by which time the line will be discontinued or the batch shade will have moved. Spares are far cheaper than retiling a room.