How many tiles do you need?
A 10 × 12 ft room of 12 × 12 in tile, with 10% waste, needs 120 square feet of coverage and 132 tiles.
Each tile’s area is length in inches times width in inches, divided by 144, to get square feet. Divide the room area by that tile area, then add waste. Straight layouts use 10%. Diagonal or herringbone layouts use 15% because more pieces end as cuts.
- Enter the room length and width in feet. Add another rectangle if a closet, hearth, or hall is part of the same order.
- Enter the tile size in inches, the size printed on the box, not the size after grout.
- Enter tiles per box so the page can round up to whole boxes.
- Pick 10% straight or 15% diagonal or herringbone.
- Open Estimate cost and type a price per box or per tile if you have a receipt.
The room does not have to be empty when you measure. Pull the tape along the finished floor line, wall to wall. If two rooms share a doorway and you want one run of tile, add both rectangles rather than guessing a single bigger box.
Vinyl plank that clicks together still uses the same square-footage math, but waste is often closer to 8 to 10% on a straight lay and more if you are wrapping a hallway with many door cuts. Carpet tiles are ordered the same way: room area divided by the face area of one tile, then waste. This page is built for ceramic, porcelain, and stone face sizes in inches; if your carton lists coverage in square feet per box, you can still enter the tile size and the tiles-per-box count from the same carton.
How to calculate square feet for tile
Multiply room length by width in feet. The area of one tile is its length in inches times its width in inches, divided by 144. A 10 × 12 ft room is 120 square feet, and 12 × 12 in tile covers 1 square foot, so 120 tiles cover the room and 132 tiles include 10% waste.
Worked example: 10 × 12 room, 12 × 12 tile
Worked example
Room: 10 ft by 12 ft. Tile: 12 in by 12 in. Waste: 10%. Ten tiles per box.
10 × 12 = 120 square feet. Each 12 × 12 tile covers 12 × 12 ÷ 144 = 1.00 square foot. Tiles to cover = 120 ÷ 1 = 120. With 10% waste, 120 × 1.10 = 132 tiles to buy. Boxes = 132 ÷ 10 = 13.2, which rounds up to 14 boxes.
That is the default result on this page. The same room with 12 × 24 in tile: each piece is 2.00 square feet, so you need 60 tiles to cover and 66 to buy at 10% waste.
If you switch to 15% for a diagonal layout, 120 × 1.15 = 138 tiles.
Tiles to buy for 100 square feet
| Tile size | Area each tile covers | To cover 100 sq ft | Buy at 10% waste | Buy at 15% waste |
|---|---|---|---|---|
| 12 × 12 in | 1.00 sq ft | 100 | 110 | 115 |
| 12 × 24 in | 2.00 sq ft | 50 | 55 | 58 |
| 6 × 6 in | 0.25 sq ft | 400 | 440 | 460 |
| 3 × 12 in | 0.25 sq ft | 400 | 440 | 460 |
Box counts depend on how the maker packs the carton. Always use the tiles-per-box number on your box, not a generic 10.
Questions
How many 12 × 12 tiles do I need for a 10 × 12 room?
How do I calculate square footage for tile?
How much extra tile should I buy for waste?
How many tiles are in a box?
How do I calculate tile for a bathroom or shower?
Do I need more tile for a herringbone layout?
How do I calculate backsplash tile?
How many tiles do I need?
Written by The BuildMath team. Formulas tested against worked examples. Updated October 21, 2026.