How the tile estimate works
The calculator divides total surface area by the face area of one tile, applies your waste percentage and rounds up to a whole tile. It then rounds the tile count again to complete boxes. The planning panel goes one step further by showing the purchased tile count, expected spares and optional box cost.
Worked example
A 4 m × 3 m floor is 12 m². A 60 cm × 30 cm tile covers 0.18 m². The theoretical requirement is 67 tiles; with 10% waste it becomes 74 tiles. With six tiles per box, the project requires 13 boxes, or 78 purchased tiles.
Pattern matters because cuts matter
| Pattern | Cutting tendency | Planning effect |
|---|---|---|
| Straight grid | Mostly perimeter cuts | Usually lower waste. |
| Running bond / offset | Repeated staggered cuts | Moderate waste. |
| Diagonal | Triangular edge cuts | Often higher waste. |
| Herringbone / complex | Many directional cuts | Usually higher again. |
The planning options provide suggested starting percentages, but the final allowance should reflect your room shape, tile fragility and installer layout.
Boxes, batch matching and spare tiles
Tiles are commonly sold in complete boxes. That means the quantity you purchase is usually higher than the exact tile count. Keeping a few unused tiles is often useful because shade, calibration and surface finish can vary between production batches, and an exact match may be hard to source years later.
Grout joints and effective module size
For pure area estimating, grout joints usually make less difference than cutting waste. For very small tiles, mosaics or wide joints, you can treat the tile plus one joint as an effective module when studying layout. For purchasing, the box coverage printed by the manufacturer is often the most reliable check.
Walls, floors and irregular rooms
For a wall, use wall width and height as the surface dimensions. For L-shaped floors, split the room into rectangles and add their areas. Subtract only large openings or fixed areas that genuinely will not receive tile; small openings can still consume tile because of surrounding cuts.
Before ordering
- Confirm the actual tile dimensions and box count.
- Check the manufacturer’s stated box coverage.
- Use a waste allowance suited to the layout, not a universal percentage.
- Keep spare pieces when future matching may be difficult.
- Order all visible tile from the same batch when practical.