Tile Calculator
Calculate how many tiles you need for a floor or wall, including a waste allowance.
How to use this tool
- Enter room length, room width, tile length, tile width and waste allowance in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your tiles needed and the full breakdown beneath it.
Find out how many tiles to buy before starting your tiling project.
⚠ This tool provides general estimates for education only and is not financial, tax or legal advice. Figures may not reflect your situation — verify with a qualified professional.
Formula
Floor area (m²) = room length × room width
Tile area (m²) = (tile length cm ÷ 100) × (tile width cm ÷ 100)
Tiles needed = ⌈ (floor area ÷ tile area) × (1 + waste % ÷ 100) ⌉
tiles = ceil((room_area / tile_area) × (1 + waste/100))
How it works
This calculator determines the number of tiles required to cover a rectangular floor or wall by dividing the total surface area by the area of one tile, then inflating the count by a user-specified waste allowance to account for cuts, breakages, and offcuts.
The result is rounded up to a whole tile using the ceiling function, ensuring you never order too few. The waste allowance is typically 10% for straight-lay patterns and 15–20% for diagonal or complex patterns.
Worked example
- Room: 5 m × 4 m. Tile: 60 cm × 60 cm. Waste allowance: 10%.
- Floor area = 5 × 4 = 20 m².
- Tile area = 0.60 × 0.60 = 0.36 m².
- Base tiles = 20 ÷ 0.36 ≈ 55.56. With 10% waste: 55.56 × 1.10 ≈ 61.11.
- Round up: ⌈61.11⌉ = 62 tiles.
Floor area = 20.0 m²; Tiles needed = 62
Common mistakes to avoid
- Omitting a waste allowance for a straight-lay pattern — even a simple grid layout produces offcuts at walls; 10% is the minimum recommended allowance.
- Entering tile size in metres instead of centimetres, which makes each tile appear 10,000x smaller and returns a wildly inflated tile count.
- Not ordering extra tiles from the same batch number — dye lots vary, and matching tiles from a new batch months later is often impossible.
Key terms
- Waste allowance
- An extra percentage of tiles added to the order to cover cuts at edges, breakages during installation, and future repairs; typically 10–15%.
- Ceiling function (⌈⌉)
- Rounds a number up to the nearest whole integer, ensuring you never order a fractional tile.
- Tile area
- The face area of a single tile in square metres, calculated from its length and width.
- Straight-lay pattern
- Tiles aligned in a grid parallel to room walls — the most material-efficient layout, typically requiring only 10% waste.
- Offcut
- The unused portion of a tile after it has been cut to fit along a room edge or around an obstacle.
Frequently asked questions
- How many tiles do I need?
- Divide the total floor area by the area of a single tile, then add a 10% waste allowance for cuts and breakage.