Tile Calculator
Enter the floor or wall size and the layout pattern to see how many boxes of tile and bags of thin-set to buy.
Quick answer
14 boxes for 132 ft² (120 ft² + 10% waste)
Includes 10% waste.
14 boxes for 132 ft² (120 ft² + 10% waste)
Your measurements
- Measure by
- Length × width of the floor
- Length
- 10 ft
- Width
- 12 ft
- Area to leave out
- —
- Pattern
- Straight
- Waste
- 10%
- Box coverage
- 10 ft²
- Tile width
- —
- Tile length
- —
- Thin-set per 50 lb bag
- 85 ft²
Buy list
Tile
14 boxes of tile
13.2 boxes exact
Thin-set mortar
2 × 50 lb bag
1.41 bags exact
Add your local prices to see a total.
Project figures
- Floor to tile
- 120 ft²
- Tile to buy for
- 132 ft²
Diagram
Not to scale where a dimension is very thin or long.
Show the math
- Floor to tile = floor area − area left out = 120 ft².
- Add 10% for cuts (straight layout): 120 ft² × 1.1 = 132 ft².
- Boxes = 132 ft² ÷ box coverage = 13.2, rounded up to 14.
- Thin-set = 120 ft² (no waste: offcuts need no mortar) ÷ coverage per bag = 1.41 bags, rounded up to 2.
Assumptions and notes
- Grout joints are ignored: tile counts assume tiles touch edge to edge, which slightly overestimates.
- Thin-set coverage assumes a 1/4 × 1/4 in square-notch trowel; larger tiles need a bigger notch and more mortar.
- Grout is not included yet.
- Quantities and cost only. For structural, load or code questions, check your local building code and a qualified professional.
How it works
This calculator works out how many boxes of tile to buy for a floor or a wall, how many bags of thin-set mortar go under them, and, if you give the tile size, how many individual tiles that is. It adds a cutting allowance that depends on the layout pattern, because some patterns waste far more tile at the edges than others.
The formula
Start with the area: length times width, or a total you measured yourself. Subtract anything that will not be tiled, such as a kitchen island or a built-in cabinet. Then add the waste allowance for the pattern and divide by the area one box covers, which is printed on the box. Thin-set is worked out from the area that actually gets tiled, without the waste allowance, because offcuts that end up in the bin never touch the mortar.
A worked example
The page opens with a 10 ft × 12 ft floor laid in a straight grid. The floor is 120 square feet. A straight layout adds 10% for cuts, so you buy tile for 132 square feet. With boxes covering 10 square feet each, that is 13.2 boxes, rounded up to 14. Thin-set at 85 square feet per 50 lb bag covers the 120 square foot floor with 1.41 bags, so you buy 2. With 12 in × 12 in tiles, the same floor takes 132 tiles.
Why the pattern changes the waste
A straight grid only cuts tiles along the walls, so 10% is usually enough. A diagonal layout cuts a triangle off every tile that meets a wall, which is why the default rises to 15%. Herringbone has the most angled cuts and defaults to 20%. The waste field follows the pattern until you type your own figure; after that your number stays, even if you change the pattern again. Large tiles, many corners and tiles you want to match from one batch are all reasons to add a little more.
Tiles, boxes and thin-set
Tile is sold by the box, so the box count is what goes on the buy list. The tile count is there to help you check a box label or plan a pattern. It ignores the grout joints between tiles, which slightly overestimates. The thin-set figure assumes a quarter-inch square-notch trowel; bigger tiles need a bigger notch and more mortar, so check the bag for your tile size and change the coverage if it differs.
Measuring tips and common mistakes
- Measure wall to wall at floor level, and include closets or alcoves you will tile.
- Leave out only areas that stay covered for good, not furniture you might move.
- Mixing up box coverage and tile size: the box label usually lists both.
- Buying exactly the rounded count; a spare box helps with future repairs.