How This Calculation Works
The tile calculator divides the total surface area by the area of a single tile. For example, if your floor is 12 m² and each tile covers 0.09 m² (30 × 30 cm), you need 12 ÷ 0.09 = 134 tiles. The result is rounded up because you can't buy a partial tile.
A waste allowance is then added to cover cuts along edges, breakage during handling, and future replacements. A 10% waste factor is standard for straightforward rectangular layouts. Diagonal or herringbone patterns generate more cuts, so 15% is recommended.
This calculator works for both floor and wall tiling — simply enter the dimensions of the surface you are covering.
Common Mistakes to Avoid
- Underestimating waste. Many first-timers assume they can cut every edge piece perfectly. Budget at least 10% for waste — more for large-format tiles or complex patterns.
- Forgetting grout lines. For small tiles with wide grout joints, the usable area per tile is slightly less. This calculator accounts for tile-to-tile coverage, but if you have 5 mm+ joints, consider adding a small extra allowance.
- Not keeping spares. Buy a few extra tiles and store them. If a tile cracks years later, the exact batch may no longer be available.
- Mixing tile sizes. Double-check that your tile dimensions are the nominal size (the size including the intended grout gap), not the actual face size. Most calculator inputs expect the nominal size.
- Ignoring pattern direction. Subway-style or brick-pattern layouts shift each row, creating more edge cuts. Factor this into your waste allowance.
Worked Example
Scenario: A bathroom floor measuring 3 m × 2 m using 30 × 30 cm tiles with 10% waste.
Step 1 — Floor area: 3 × 2 = 6 m².
Step 2 — Tile area: 0.30 × 0.30 = 0.09 m² per tile.
Step 3 — Tiles needed: 6 ÷ 0.09 = 67 tiles (rounded up from 66.7).
Step 4 — Add waste: 67 × 1.10 = 74 tiles. Buy 74 tiles.