Tile Calculator
Estimate how many tiles and boxes to buy for a floor or wall, with your own waste allowance, spare tiles, box coverage and total cost.
What is a tile calculator?
This tile calculator estimates how many tiles and boxes to buy for a rectangular floor or wall. Enter the Room length and Room width in feet, the Tile length and Tile width in inches, a Waste allowance in percent, the Tiles per box and, if you know it, the Price per box.
The headline result is Tiles needed (with waste), followed by the Boxes to buy. Below them you can check the working: the Tiles to cover the floor exactly (no waste), the Floor area in square feet, the Area of one tile, the Area covered by the boxes you buy, the Spare tiles beyond the exact floor area and the Estimated total cost.
Two parts of the estimate are up to you. The waste allowance covers tiles lost to cuts at walls and corners, breakage and pattern matching, and how much you need depends on the layout, the room shape and the tile; there is no single correct percentage, and the 10% the form starts with is only a starting value. The calculator also ignores grout joints and works on one rectangle at a time. The sections below show how each of these affects the count, so you can decide what to order.
Formula
- Floor area (sq ft) = room length × room width, both in feet.
- Area of one tile (sq ft) = tile length × tile width ÷ 144, because a square foot is 12 × 12 = 144 square inches.
- Exact count = floor area ÷ area of one tile. Rounded up to a whole tile, this is Tiles to cover the floor exactly (no waste).
- Tiles needed = exact count × (1 + waste % ÷ 100), rounded up. The unrounded exact count is used here.
- Boxes to buy = tiles needed ÷ tiles per box, rounded up, because boxes are sold whole.
- Area covered = boxes × tiles per box × area of one tile, and spare tiles = boxes × tiles per box − the exact count rounded up.
- Estimated total cost = boxes × price per box. With the price left at 0, it shows a dash.
The exact count assumes every tile is used in full, with no gaps and no offcuts. Real floors lose part of each tile cut to fit an edge, which is what the waste allowance stands in for.
Tiles per 100 square feet
For a 10 × 10 ft area with no waste, the calculator gives:
| Tile size (in) | Area of one tile (sq ft) | Tiles, no waste |
|---|---|---|
| 3 × 6 | 0.125 | 800 |
| 4 × 4 | 0.111 | 900 |
| 6 × 6 | 0.250 | 400 |
| 6 × 24 | 1.000 | 100 |
| 12 × 12 | 1.000 | 100 |
| 12 × 24 | 2.000 | 50 |
| 18 × 18 | 2.250 | 45 |
| 24 × 24 | 4.000 | 25 |
For 18 × 18 tiles, 100 ÷ 2.25 = 44.4, which rounds up to 45 whole tiles.
Worked example
Example 1: a 10 × 8 ft bathroom with 12 × 12 tiles
Waste allowance 10%, 10 tiles per box, $45 per box.
- Floor area: 10 × 8 = 80.0 sq ft. Area of one tile: 12 × 12 ÷ 144 = 1.000 sq ft.
- Exact count: 80 ÷ 1 = 80 tiles.
- With waste: 80 × 1.10 = 88 tiles.
- Boxes: 88 ÷ 10 = 8.8, rounded up to 9 boxes, which hold 90 tiles and cover 90.0 sq ft.
- Spare tiles: 90 − 80 = 10. Estimated total cost: 9 × $45 = $405.00.
Example 2: a 14 × 11.5 ft kitchen with 12 × 24 tiles, at two waste allowances
Floor area 161.0 sq ft, tile area 2.000 sq ft, so the exact count is 80.5, shown as 81 tiles. Boxes hold 8 tiles at $60.
| Waste allowance | Tiles needed | Boxes to buy | Spare tiles | Estimated total cost |
|---|---|---|---|---|
| 10% | 80.5 × 1.10 = 88.55 → 89 | 12 | 15 | $720.00 |
| 15% | 80.5 × 1.15 = 92.575 → 93 | 12 | 15 | $720.00 |
Both allowances round up to the same 12 boxes (96 tiles, 192.0 sq ft), so in this case choosing the higher allowance costs nothing extra. Trying two or three percentages shows when that happens.
Example 3: a subway-tile backsplash
A wall 10 ft long and 18 in (1.5 ft) high, with 3 × 6 in tiles, a 15% allowance, 40 tiles per box and $30 per box: the area is 15.0 sq ft, each tile is 0.125 sq ft, the exact count is 120 tiles and the count with waste is 120 × 1.15 = 138 tiles. That needs 138 ÷ 40 = 3.45, so 4 boxes (160 tiles), with 40 spare tiles and an estimated total cost of $120.00.
How to use this calculator
- Measure the room's length and width in feet and enter them as Room length and Room width. Convert inches to a decimal of a foot: 10 ft 6 in is 10.5 ft.
- Enter the Tile length and Tile width in inches, using the dimensions printed on the box or the product sheet.
- Set the Waste allowance for your layout, from 0 to 50%. Use the manufacturer's or your installer's figure if you have one.
- Enter Tiles per box and, optionally, Price per box.
- Read Tiles needed (with waste) and Boxes to buy, then check the spare tiles and the area covered.
Choosing a waste allowance
- Conventions differ, so treat any percentage as a planning assumption, not a rule. A layout with more cut tiles, such as a diagonal or herringbone pattern, or a room with many corners, closets and pipes, produces more offcuts than a plain rectangle laid straight.
- Tile manufacturer Daltile recommends buying approximately 10% more tile than you anticipate needing and keeping it as "attic stock" to replace broken tiles later, because tile from a later production run may not match exactly.
- If you are unsure, run two or three allowances and compare the Boxes to buy, as in Example 2.
Common mistakes
- Entering the room in inches or the tile in feet. The room is in feet and the tile is in inches.
- Typing 10.6 for 10 ft 6 in. Six inches is 0.5 ft, so the value is 10.5.
- Reading Tiles to cover the floor exactly as the amount to buy. It leaves nothing for cuts or breakage.
To add sales tax to the estimated total, use the sales tax calculator. The fraction calculator helps with measurements such as 11 3/8 in, and the Pythagorean theorem calculator lets you check whether a room's corners are square from its diagonal.
Sources
- Daltile — Tile & Natural Stone FAQs (attic stock and the approximately 10% extra recommendation)
Frequently asked questions
What waste allowance should I use?
There is no single standard. The right allowance depends on how many tiles must be cut, the pattern, the room shape, the tile's size and how many spares you want to keep. Daltile's recommendation of approximately 10% extra is one manufacturer's figure for attic stock; other manufacturers and installers may suggest a different amount for your tile and layout. Ask for it, enter it, and compare a higher figure to see whether it changes the number of boxes.
Does the calculator account for grout lines?
No. It divides the floor area by the face of one tile, as if the tiles touched. Grout joints mean each tile covers a little more than its own face, so the count is slightly high. You can see the size of the effect by adding the joint width to each tile dimension: for a 10 × 8 ft floor with 12 × 12 tiles, entering 12.25 × 12.25 (a 1/4 in joint) gives 77 exact tiles instead of 80. With 3 × 6 tiles, entering 3.25 × 6.25 gives 568 instead of 640, so the effect is larger for small tiles. Leaving the count as it is simply adds a small margin.
How do I measure an L-shaped room or a room with a closet?
Split the floor into rectangles, work out each area and add them. A 12 × 10 ft room with a 6 × 4 ft alcove is 120 + 24 = 144 sq ft. Because the calculator only multiplies length by width, you can enter 144 as the Room length and 1 as the Room width. With 18 × 18 tiles, a 10% allowance and 6 tiles per box, that gives 64 exact tiles, 71 tiles needed and 12 boxes. Leave out any area you will not tile.
Can I use it for a wall or a shower?
Yes. Enter the wall's width as the Room length and its height as the Room width, and run each wall separately or add their areas. Subtract windows and doors from the area first. The Floor area line then shows the wall area.
My box is labeled in square feet, not tiles. What do I enter?
Divide the square feet per box by the area of one tile. A box of 12 × 24 tiles labeled 16 sq ft holds 16 ÷ 2 = 8 tiles. The calculator needs a whole number of tiles per box and rounds a decimal down.
Why does it show so many spare tiles?
Because boxes are sold whole and the spare count is measured against Tiles to cover the floor exactly, not the count with waste. In Example 1, the 10 spare tiles are what is left of 9 boxes after 80 full tiles; your cut pieces and any breakage come out of those same 10 tiles. If a full extra box seems like too much, compare the Area covered by the boxes you buy with your floor area.
Does the estimated cost include grout, thinset or tax?
No. It is only boxes to buy × price per box. Setting materials, trim pieces, underlayment, tools, delivery, labor and sales tax are not included, and the cost line shows a dash when the price per box is 0.
Should I buy all the tile at once?
Daltile advises keeping extra tile from the same production run, noting that the dye lot and printing process can change slightly over the years. Buying the whole quantity, including spares, in one order makes a later repair easier to match.