Tile calculator
Tiles = area ÷ area of one tile (joint included). A 12 × 10 ft floor in 12 × 24 in tiles with 1/8 in joints takes 60 tiles, before any margin for cuts.
- Checked on thousands of cases
- Updated November 5, 2026
Optional, printed on the box
Tiles needed
Area: 120 ft²
Rounded up to whole tiles. Cuts are not planned: add a margin that suits your layout.
Quick challenge
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Test yourself: every answer is computed by the tool, and the wrong choices are the most common traps.
How it works
Formula: Tiles = area ÷ ((tile length + joint) × (tile width + joint))
The calculator divides the area of the floor or wall by the area that one tile covers, joint included: (length + joint) × (width + joint). It rounds up to whole tiles, then to whole boxes if you enter the number of tiles per box. Cuts along walls and around obstacles create waste that depends on the layout (straight, diagonal, herringbone) and on the room: add the margin you want in the 'Margin' field. The calculator doesn't plan the layout of the cuts.
Tiles per 100 ft² by size (no joint, no margin)
| Tile size | Tiles per 100 ft² |
|---|---|
| 6 × 6 in | 400 |
| 12 × 12 in | 100 |
| 12 × 24 in | 50 |
| 18 × 18 in | 45 |
| 24 × 24 in | 25 |
Frequently asked questions
How do I calculate how many tiles I need?
Divide the area by the area of one tile. 120 ft² in 12 × 24 in tiles (2 ft² each) = 60 tiles. Joints slightly reduce the number; cuts increase it.
How much extra tile should I buy?
It depends on the layout and on the room: a diagonal or herringbone pattern and many corners create more offcuts. Enter your margin in percent; keeping a few spare tiles also helps for later repairs.
Does the joint width matter?
A little: with large tiles and thin joints the difference is small, with small tiles and wide joints it becomes noticeable. The calculator includes it.