Tile Calculator
Work out how many tiles and boxes you need for a floor or wall, allowing for grout joints and waste.
About the Tile Calculator
Enter the area to tile, the tile size, the grout joint width, a waste allowance and how many tiles come in a box. The calculator gives the number of tiles and boxes to buy.
Each tile covers its own area plus half a grout joint on every side. Add waste for cuts and breakages: 10% for straight layouts, 15% for diagonal, more for large-format tiles in small rooms.
The formula
Tiles = ⌈area ÷ ((width + joint) × (length + joint)) × (1 + waste)⌉
Worked example
12 m² of 60 × 60 cm tiles with 3 mm joints and 10% waste
- Each tile plus joint covers 0.603 × 0.603 = 0.364 m²
- 12 ÷ 0.364 = 33 tiles; with 10% waste, 37
- At 4 per box: 10 boxes
Things to keep in mind
- Adhesive, grout, trims and spacers are bought separately.
Questions people ask
What joint width should I use?
2–3 mm for rectified tiles, 3–5 mm for most floor tiles, wider for rustic tiles.
Do I need the same batch?
Yes, check the shade and batch code on every box.
How do I tile a wall with a window?
Work out the wall area, subtract the window, and keep the full waste allowance because of the extra cuts.