Tile Calculator (2026)
Find out exactly how many tiles and boxes your room needs, including waste, plus the total cost.
Calculate Your Tiles
Measure the longest wall-to-wall side of the room in feet.
Measure the shorter wall-to-wall side of the room in feet.
The longer side of one tile, in inches, as printed on the box.
The shorter side of one tile, in inches, as printed on the box.
10% covers straight-lay cuts and breakage. Use 15% for diagonal layouts or rooms with many corners.
The tile price per square foot from the store, before tax and grout.
Tiles and boxes are always rounded up: you cannot buy part of a tile or part of a box. Total cost is the tiles you need, including waste, times the tile area times the price per square foot, before tax, grout, adhesive, and labor.
How the Math Works
A tile job is a simple area problem with one unit conversion in the middle. First, multiply the room length by the room width, both in feet, to get the floor area in square feet. Then work out the area of one tile: multiply its length by its width in inches and divide by 144, because one square foot equals 144 square inches. Divide the floor area by the tile area to get the exact tile count, then add the waste percentage and round up, since you cannot buy a fraction of a tile. Boxes are the tile count divided by 10, rounded up again.
Tile area (sq ft) = tile length (in) x tile width (in) / 144
Tiles (no waste) = floor area / tile area
Tiles (with waste) = tiles (no waste) x (1 + waste % / 100), rounded UP
Boxes = tiles (with waste) / 10, rounded UP
Total cost = tiles (with waste) x tile area x price per square foot
Waste Chart: Tiles Needed for Common Room Sizes
Waste is the extra tile you buy for cuts, breakage, and spares. Straight layouts in square rooms need about 10%; diagonal layouts, herringbone patterns, and rooms with lots of corners, niches, or angled walls need 15% or more. The table below uses 12 x 12 inch tiles (1 square foot each) at the standard 10% waste allowance.
| Room size | Floor area | Tiles (no waste) | Tiles (10% waste) | Boxes (10 per box) |
|---|---|---|---|---|
| 10 x 10 ft | 100 sq ft | 100 | 110 | 11 |
| 12 x 10 ft | 120 sq ft | 120 | 132 | 14 |
| 12 x 12 ft | 144 sq ft | 144 | 159 | 16 |
| 15 x 12 ft | 180 sq ft | 180 | 198 | 20 |
| 20 x 15 ft | 300 sq ft | 300 | 330 | 33 |
Common Tile Sizes and Tiles per Square Foot
Tile size changes the count more than most people expect, because a tile’s area grows with the square of its side. A 24 x 24 inch tile covers four times the area of a 12 x 12 inch tile, so it needs a quarter of the pieces, but the waste percentage stays the same. Use this table to sanity-check the calculator’s output for your tile size.
| Tile size | Area per tile | Tiles per square foot |
|---|---|---|
| 4 x 12 in | 0.33 sq ft | 3.00 |
| 6 x 12 in | 0.50 sq ft | 2.00 |
| 6 x 24 in | 1.00 sq ft | 1.00 |
| 12 x 12 in | 1.00 sq ft | 1.00 |
| 18 x 18 in | 2.25 sq ft | 0.44 |
| 24 x 24 in | 4.00 sq ft | 0.25 |
Worked Example: 12 x 10 Foot Room, 12 x 12 Inch Tile
| Calculation | Result | |
|---|---|---|
| Floor area | 12 x 10 | 120 sq ft |
| Tile area | 12 x 12 / 144 | 1.00 sq ft |
| Tiles (no waste) | 120 / 1.00 | 120 tiles |
| Tiles (10% waste) | 120 x 1.10, rounded up | 132 tiles |
| Boxes | 132 / 10, rounded up | 14 boxes |
| Total cost | 132 x 1.00 x $3.50 | $462.00 |
Note that 14 boxes hold 140 tiles, so you will have 8 spare tiles after the job. Keep those spares: a matching tile from the same batch is worth far more than the few dollars it cost, because dye lots change and a discontinued tile can be impossible to match later.
Tips Before You Buy
- Measure wall to wall, not the visible floor. Tile runs under vanities, tubs, and appliances too, so measure the full room, then subtract only large permanent fixtures you are sure will never be tiled under.
- Buy all boxes from one dye lot. Check the lot number on the box and buy every box at once; tiles from different lots can differ visibly in shade.
- Diagonal and herringbone layouts need 15% waste or more. Angled cuts produce more offcuts than straight rows, so raise the waste allowance before you order.
- Round up twice. Tiles round up first, then boxes round up again. That second rounding is why a job needing 132 tiles takes 14 boxes, not 13.2.
- Budget beyond the tile. Grout, adhesive, underlayment, spacers, and trim are not in this calculator’s cost. Add roughly 15 to 25% on top of the tile cost for materials, or get a labor quote separately.
- Keep spare tiles. Store at least a few full tiles from the same batch for future repairs. A cracked tile with no matching spare means retiling a whole section.
