Tile Calculator
Enter the room's length and width and your tile size, and the calculator works out the floor area, how many tiles that takes (plus a waste allowance for cuts and breakage), and — the number you actually order — how many boxes to buy. It also estimates the thinset mortar and grout you'll need to set and finish them.
Your measurements
The longer side of the room or wall you're tiling.
The shorter side. For a wall, this is the height.
The face dimensions of one tile. Pick "Custom size" to type your own under Advanced options.
How many tiles come in one box — printed on the box or the product page. Larger tiles come fewer to a box.
Tile to buy
14 boxes
132 tiles · 120 ft² · incl. 10% waste
What to buy
- Tile — 12" × 12"
- 14 boxes
- Thinset mortar
- 2 bags
- Grout
- 2 bags
Tile is sold by the box, not the piece — 10 tiles per box here. That's 132 tiles, which covers your 120 ft² with cuts to spare.
Thinset is the cement-based adhesive that bonds tile to the floor. A 50 lb bag covers roughly 40–90 ft² depending on tile size and the notched trowel used.
Grout fills the joints between tiles after they're set. Smaller tiles and wider joints use more.
Estimates only. Verify against your supplier's coverage figures before ordering.
Footprint
Footprint to scale
The numbers
- Area to tile
- 120 ft²
- One tile covers
- 1 ft²
- Tiles (no waste)
- 120 tiles
- Tiles with waste (+10%)
- 132 tiles
- Boxes to order
- 14 boxes(covers 140 ft²)
A 12" × 12" tile's face area.
The bare minimum if nothing broke and you never cut a tile.
Extra tiles for the pieces you cut at the edges and the odd one that cracks.
Rounded up to whole boxes — keep the leftovers for future repairs.
The formula
Area = Length × Width · Tiles = ⌈Area × (1 + waste %) ÷ tile ft²⌉ · Boxes = ⌈Tiles ÷ tiles per box⌉
Example: A 12 × 10 ft room (120 ft²) in 12" × 12" tile (1 ft² each) with 10% waste needs 132 tiles. At 10 tiles per box that's 14 boxes, plus about 2 bags of thinset and 2 bags of grout.
How it works
- 1Multiply room length × width to get the area to tile, in square feet.
- 2Work out one tile's face area: convert its size to feet and multiply (a 12 × 12 in tile is 1 ft²).
- 3Divide the area by the tile area for the bare tile count, then add 10% (15% for diagonal or large-format) for cuts and breakage and round up.
- 4Divide by the tiles-per-box and round up — you buy whole boxes, so keep the spares for repairs.
- 5Add thinset mortar to set the tile and grout to fill the joints; both are coverage-based and vary with tile size and trowel.
Frequently asked questions
How much tile do I need for a room?
Measure the room's length and width, multiply for the square footage, then divide by one tile's coverage. Add 10% for waste on a standard layout (15% for diagonal or large-format tile) and round up to whole boxes. A 120 ft² room in 12-inch tile needs about 132 tiles with 10% waste.
How much extra tile should I buy for waste?
Add about 10% for a straight layout, and 15% for diagonal/herringbone patterns or large-format tile, where you cut more pieces and breakage is costlier. Always buy whole boxes and keep the leftovers — dye lots change, so matching tile later is hard.
How many bags of thinset do I need?
A 50 lb bag of thinset covers roughly 40–90 ft² depending on tile size and the notched trowel you use — small tile with a 1/4-inch trowel goes furthest, large-format tile with a bigger trowel uses much more. For a typical floor, plan on about one bag per 60 ft².
How much grout do I need?
Grout depends on tile size, joint width and joint depth: smaller tiles and wider joints mean more grout. As a rough guide a 25 lb bag covers about 100 ft² of medium tile with standard joints. Tile-store grout calculators fine-tune it from your exact tile and joint size.