How to calculate how many tiles you need
The number of tiles depends on the area you are covering and the size of each tile:
Tiles needed = area ÷ area of one tile × (1 + waste %)
This calculator converts your tile dimensions from inches to square feet (width × height ÷ 144), divides your total area by that figure, adds a waste allowance, and rounds up. The same method works for both floors and walls.
How much extra tile should you buy?
| Layout | Recommended waste |
|---|---|
| Straight, grid layout | 10% |
| Diagonal layout | 15% |
| Complex rooms or many cuts | 15–20% |
| Small mosaic or patterned tile | 15%+ |
Coverage by tile size
Tile is sold by the box, but it helps to know how much floor one tile covers:
| Tile size | Area per tile | Tiles per 100 sq ft |
|---|---|---|
| 12 × 12 in | 1.00 sq ft | 100 |
| 18 × 18 in | 2.25 sq ft | ~45 |
| 12 × 24 in | 2.00 sq ft | 50 |
| 6 × 24 in (plank) | 1.00 sq ft | 100 |
| 3 × 6 in (subway) | 0.125 sq ft | ~800 |
Add your waste allowance on top of these counts.
Porcelain, ceramic, or natural stone?
- Ceramic. Affordable and easy to cut; great for walls and light-traffic floors.
- Porcelain. Denser, harder, and more water-resistant — the durable choice for floors, wet areas, and outdoors. Look for a PEI rating of 3 or higher for floors.
- Natural stone (marble, travertine, slate). Beautiful and unique, but porous — most needs sealing and gentler cleaners.
Don't forget the rest of the job
Tiles are only part of the order. You'll also need thinset mortar and grout — both sized by your area, tile size, and trowel or joint width — plus spacers, a notched trowel, and edge trim. Buy all your tile from one dye lot so the color matches, and keep a few spares for repairs.
How much does tile cost?
Tile itself ranges widely — roughly $1–$10 per tile (about $1–$15+ per sq ft) from budget ceramic to natural stone and designer porcelain. Professional installation typically adds $5–$12 per sq ft depending on tile size, layout, and surface prep.
Planning your tile layout
Where you start the first tile decides how the edges look. Find the center of the room, snap two perpendicular layout lines, and dry-lay a row in each direction before spreading any thinset. The goal is to balance the cut tiles on opposite walls so you don't end up with a full tile on one side and a thin sliver on the other — slivers are hard to cut and look off. Shift your starting lines by half a tile if that gives cleaner edges. Plan so cut edges fall in less-visible spots (under cabinets, along the least-seen wall) and the main sightline as you enter the room runs full tiles.