What this tile calculator does
Running out of tile halfway through a job is expensive: a second trip to the store, and a real chance the new batch comes from a different production run with a slightly different shade. This calculator tells you upfront how much ceramic or porcelain tile to buy. Enter your floor dimensions (or the area in square meters), pick a tile size and a waste percentage, and it returns the square meters to purchase, the number of tiles and the number of boxes. Everything runs in your browser — nothing is sent to a server.
The waste allowance covers cuts along walls, broken pieces and awkward corners. The trade standard is 10% for a straight layout and 15% for diagonal installs, and buying it all at once keeps every tile in the same batch and shade.
How to use it
- Choose how to enter the area: length × width in meters, or direct m² if you already measured it.
- Pick the tile size: 20x30, 30x30, 45x45, 60x60 cm or a custom size in centimeters.
- Set the waste percentage: 10% for a straight pattern, 15% for diagonal layouts or rooms with lots of cuts.
- Enter the m² per box printed on the manufacturer’s packaging (1.44 m² is typical for 60x60 porcelain).
- Read the result — m² to buy, tiles and boxes — and copy it with one click.
The formula
The calculator follows the same steps a professional installer uses:
| Step | Calculation |
|---|---|
| Base area | length × width (in meters) |
| Area to buy | base area × (1 + waste ÷ 100) |
| Area of one tile | (width cm ÷ 100) × (height cm ÷ 100) |
| Tiles | area to buy ÷ tile area, rounded up |
| Boxes | area to buy ÷ m² per box, rounded up |
Both final figures round up because tiles and boxes are only sold whole.
Worked example
A bedroom measuring 3.5 m by 4 m will get 30x30 cm ceramic tile in a straight layout (10% waste), sold in boxes that cover 1.44 m²:
- Base area: 3.5 × 4 = 14 m².
- Area to buy: 14 × 1.10 = 15.4 m².
- Area of each tile: 0.30 × 0.30 = 0.09 m².
- Tiles: 15.4 ÷ 0.09 = 171.1 → 172 tiles.
- Boxes: 15.4 ÷ 1.44 = 10.7 → 11 boxes, covering 15.84 m² in total.
Those 11 boxes leave a small surplus — exactly what you want on hand for future repairs.
Buying tips
- Buy the whole order from the same batch and shade code (printed on each box); different runs can vary in color.
- Keep 3 or 4 spare tiles after the job. Finding the exact same model years later is nearly impossible.
- For L-shaped rooms or floors with closets and columns, split the space into rectangles, add up the areas and use the direct m² mode.
- Budget separately for thinset mortar and grout — their quantities depend on tile format and trowel size, not just floor area.
Frequently asked questions
How much waste should I add?
Use 10% for a straight grid layout in a regular room. Go up to 15% for diagonal (45-degree) installs, because every row ending at a wall produces two triangular offcuts. Very irregular rooms or large-format tiles such as 60x120 may justify up to 20%.
How many tiles come in a box?
It varies by format and brand. Typical references: 60x60 usually ships 4 tiles per box (1.44 m²), 45x45 ships 8 (1.62 m²), and 30x30 anywhere from 10 to 17 tiles. Check the label and adjust the m² per box field to match.
Does this work for walls too?
Yes. The math is identical: treat the wall’s height × width as the floor’s length × width, subtract the area of doors and windows yourself, and enter the remainder using the direct m² mode.
Why does it tell me to buy more m² than my floor measures?
Because of waste. Every cut against a wall, every corner piece and every tile that cracks during installation uses material that never shows on the finished floor. The extra percentage keeps you from coming up short mid-job.
The boxes cover more than I need — is that wrong?
No, it is expected. Boxes are sold whole, so the calculator always rounds up. The surplus acts as your repair reserve. If the leftover exceeds a full box, ask the store whether they sell loose tiles from the same batch.