To calculate the number of tiles needed, measure the length and width of the area you want to tile and multiply them to find the total area. Then, measure the length and width of a single tile and multiply them to find the tile area. Divide the total area by the tile area to get the base number of tiles. Finally, add 10-15% for waste and cuts. This calculator does all the math for you instantly.

The waste factor (or overage) is the extra percentage of tiles you should buy to account for cuts, breakage, and mistakes during installation. A standard waste factor is 10% for straightforward rectangular rooms and standard layouts. If you are tiling a diagonal pattern, a herringbone layout, or a room with many corners and obstructions, you should increase the waste factor to 15-20%.

Calculating by area (Total Area ÷ Tile Area) is generally accurate for estimating material. However, calculating by grid (Rows × Columns) is often more precise for rectangular rooms because it accounts for the fact that you cannot always use the offcut from one side of the room on the opposite side. This calculator provides both methods in the breakdown so you can choose the most appropriate number.

For diagonal or herringbone patterns, you will generate more cuts and waste than a standard straight layout. You should calculate your base number of tiles using the area method, but increase your waste factor from the standard 10% to 15-20%. This ensures you have enough full tiles to complete the intricate cuts required at the edges of the room.

The number of tiles in a box varies significantly depending on the size and thickness of the tile. For example, a box of large 600x600mm floor tiles might contain 4 tiles (covering 1.44 sq m), while a box of small 100x100mm mosaic tiles might contain 10 tiles (covering 1 sq m). Always check the packaging or the supplier’s website for the exact coverage per box, and enter that number into this calculator to find out how many boxes to buy.

Grout lines typically add 2-3mm between each tile. While this slightly reduces the number of tiles needed, the difference is usually negligible for large rooms. However, if you are using very small tiles (like mosaics) or very wide grout lines, it can add up. For most standard projects, you can ignore the grout line width in your initial calculation and rely on the 10% waste factor to cover any discrepancies.

Measure the longest length and the widest width of the room in a straight line. If your room is L-shaped or has alcoves, divide the space into smaller rectangular sections, calculate the area for each section separately, and then add them together. Always measure in the unit you are most comfortable with, and ensure you are measuring the actual floor or wall space, not just the skirting board length.

The standard waste percentage for tiles is 10%. This is sufficient for most standard rectangular rooms with a straight (grid) layout. If you are using large format tiles, tiling a diagonal pattern, or working in a room with many pillars, cabinets, or irregular angles, you should increase the waste factor to 15% or even 20% to ensure you don’t run out of tiles mid-project.