How Much Tile for a Floor?
One method works for every floor. The only decision is the waste allowance.
Divide the floor area by the area of one tile, add your waste allowance, then convert to boxes and round up. For 150 square feet of 12×12 tile at 10 % waste that is 17 boxes. The only judgement call is the waste percentage, and getting it wrong is the most common reason people run out.
Estimates only. Textured walls, high ceilings, sprayers and major colour changes can all increase the amount you need. Always buy slightly more than the calculation suggests.
Floor tile by room, in 12x12
| Area | Surface | Tile size | Tiles | Boxes | Tile cost |
|---|---|---|---|---|---|
| Bathroom, 40 sq ft | 40 sq ft | 12" × 12" | 44 | 5 boxes | $175 |
| Hallway, 60 sq ft | 60 sq ft | 12" × 12" | 66 | 7 boxes | $245 |
| Bedroom, 120 sq ft | 120 sq ft | 12" × 12" | 132 | 14 boxes | $490 |
| Living room, 200 sq ft | 200 sq ft | 12" × 12" | 220 | 22 boxes | $770 |
| Whole ground floor, 600 sq ft | 600 sq ft | 12" × 12" | 660 | 66 boxes | $2,310 |
| Living room, 200 sq ft, diagonal | 200 sq ft | 18" × 18" | 103 | 18 boxes | $630 |
10 % waste for a straight lay. Diagonal layouts need 15 %, and herringbone or complex patterns 20 %.
The four steps
- Measure the area. Break the floor into rectangles, measure each, and add them up. Include the strips under doorways and in alcoves.
- Work out the area of one tile. Multiply length by width in inches and divide by 144. A 12×12 tile is exactly 1 square foot; a 12×24 is 2 square feet.
- Add the waste allowance. 10 % straight, 15 % diagonal, 20 % for pattern layouts or complicated rooms.
- Convert to boxes and round up. Tiles per box varies by product — check the box before ordering, because large-format tile is often 4 or 6 to a box rather than 10.
How much waste is enough?
The waste allowance covers three separate things, and it is worth understanding which applies to you:
- Cuts. Every edge tile is cut, and the offcut is usually unusable. A simple square room wastes little; a room with an island, a chimney breast or a bay window wastes a lot.
- Breakage. Tiles crack during cutting, especially porcelain and large-format tile.
- Spares. You want tiles left over after the job. Not for the current floor — for the repair in five years, when a chair leg cracks a tile and the colour has been discontinued.
That third reason is why the answer is never zero waste, even for a perfect rectangle.
Buy all the tile at once
Tile is manufactured in dye lots. Tiles from one production run share a colour; the next run can be subtly different, and on a large floor the difference is visible where the two batches meet.
This means two things:
- Order everything in one go, including the waste and the spares, from the same lot number. Check the lot number on each box when it arrives.
- Mix boxes as you lay. Take tiles from two or three boxes at a time rather than finishing one box before opening the next. It blends any slight variation across the whole floor instead of creating a visible band.
Frequently asked questions
How do I calculate how much floor tile I need?
Measure the area in square feet, divide by the area of one tile, add 10 to 20 % for waste, then convert to boxes and round up.
How much waste should I allow for floor tile?
10 % for a straight lay in a simple room, 15 % for diagonal, and 20 % for herringbone or a room with lots of cuts. Never zero — you need spares for future repairs.
How many 12x12 tiles are in a square foot?
Exactly one. A 12x12 tile is 144 square inches, which is 1 square foot. A 6x6 tile is four to a square foot, and a 12x24 tile is half a square foot each.
Can I mix tile from different boxes?
You should. Take from two or three boxes at a time so any slight shade variation blends across the floor instead of forming a visible band when you change boxes.