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.
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. Change any measurement in the calculator to get your own numbers.
| 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
| 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.