Room & Tile Measurements
How to calculate tiles for a room
First calculate the room area by multiplying its length by width. Convert the room and tile measurements to the same unit, then divide the room area by the area covered by one tile. The calculator rounds up to a whole tile because tiles cannot normally be purchased as fractions.
Allow for tile wastage
Cutting, breakage, edge pieces and installation patterns can create waste. A 10% allowance is a useful starting point for a straightforward project, while rooms with many corners, diagonal layouts or complex patterns may require a different allowance.
Example tile calculation
For a 20 ft × 15 ft room, the floor area is 300 sq ft. If each tile covers 2 ft × 2 ft, one tile covers 4 sq ft, so 75 tiles are needed before wastage. With 10% wastage, the recommended quantity is rounded up to 83 tiles.
Tile calculator for flooring and walls
This tool can help with basic flooring or wall-tile planning. Enter the actual dimensions of the project and tile package information where available. For a final purchase quantity, also consider manufacturer packaging, spare tiles and the installation method.
Plan tiles for rooms with more than one section
For an L-shaped room, split the floor into rectangles, calculate each rectangle's area, and add the areas before estimating tiles. For wall tiles, measure each wall separately and subtract doors or windows when you need the net tiled area. Keep floor and wall areas separate so they are not accidentally added together.
Wastage, cartons and purchase quantity
The wastage percentage is an estimate, not a guarantee. Straight layouts in a simple rectangular room may need less cutting than diagonal layouts, small rooms with many corners, patterned designs or fragile materials. The calculator rounds the tile count up to a whole tile, but suppliers may sell tiles in cartons; use the manufacturer's coverage per carton to round up again before ordering.
If the calculated requirement is 83 tiles, for example, and a carton contains 6 tiles, you would need 14 cartons (84 tiles). Keep a few spare tiles for future repairs where practical, and confirm the final quantity with the installer or supplier. Tile thickness, grout gaps, substrate preparation and the laying pattern are not included in this area estimate.
Check the assumptions before buying
- Measure the actual room rather than relying only on a floor plan.
- Use the same unit for both dimensions of each room and tile.
- Enter the price per individual tile, not the price per carton, in the optional price field.
- Compare the estimated coverage and quantity with the product packaging.
Related PenniTools calculators
Use the Square Feet Calculator to calculate room area, the Paint Calculator for paint estimates, and the Concrete Calculator for concrete volume.
Worked example: a 12 ft × 10 ft room
A 12 ft by 10 ft room has an area of 120 sq ft. If each tile is 2 ft by 2 ft, one tile covers 4 sq ft, so the theoretical requirement is 120 ÷ 4 = 30 tiles. With a 10% allowance for cuts and breakage, 30 × 1.10 = 33 tiles. Round up to whole tiles and then check how many tiles come in each carton.
Why the estimate can differ from the actual order
- Diagonal patterns and many corners usually create more offcuts than a straight layout.
- Tiles may need to be cut around columns, doorways, drains or fixtures.
- Tiles from different batches can vary slightly in shade or size; retain spare tiles for future repairs.
- The calculator assumes a rectangular area and uniform tile size. It does not create a layout plan or account for grout-joint spacing.
Before you purchase
Measure the finished surface, confirm the exact tile dimensions printed on the carton, and use the manufacturer's coverage per box where available. If a room has alcoves or multiple sections, calculate each section separately and add the results. Treat the wastage percentage as a planning allowance rather than a guarantee.
For help converting room measurements, see the Square Feet & Area Guide. For wall painting, use the Paint Calculator.