How to Calculate Tiles for Walls and Floors
Whether you're tiling a kitchen splashback, a wet room, or a large hallway floor, buying the exact right number of tiles is critical. Because ceramic and porcelain tiles are fired in large factory batches, the color and size can vary slightly from batch to batch. If you run short and order an extra box later, the new tiles might not perfectly match the ones you've already laid.
Our Tile Calculator helps you avoid this disaster by working out the exact number of tiles needed for your room's surface area, while factoring in a safe allowance for breakages and tricky cuts around sockets, pipes, and windows.
How to Measure Your Room
To calculate the square metreage (m²) of a wall or floor, simply multiply its Length by its Height (or Width) in metres. For example, a bathroom floor that is 2m wide and 3m long has an area of 6m².
If you are tiling multiple walls, calculate the area of each wall separately and add them together to get your total m² figure.
Factoring in Grout Lines
A standard grout line is 2mm to 3mm wide. While small, across a large room, these gaps add up. For example, over a 10-metre run, 3mm gaps between 300mm tiles can save you an entire tile. Our calculator adds the grout width to the tile dimensions to provide a mathematically precise count, helping you avoid over-ordering.
Calculating Tile Waste Options
Tiles cannot be bent or stretched; they must be cut. Every cut produces offcuts that usually cannot be reused elsewhere on the wall.
- 10% Allowance (Standard): Suitable for most standard square rooms and straight, grid-like tile-laying patterns.
- 15% Allowance (Complex): Required if you are laying tiles in a diagonal pattern, a herringbone pattern, or if the room has many complex obstacles (like a complicated bathroom suite or lots of electrical sockets).