How to calculate tile
Find the surface area and divide it by one tile's area using consistent units. Round up to a whole tile, then add waste for cuts, breakage, and future repairs.
Tile formula
Base tiles = surface area ÷ tile area. Recommended tiles equal base tiles × (1 + waste percentage), rounded up. Boxes and cost are calculated only when package information is supplied.
Worked example
A 12 × 10 foot floor is 120 square feet. With 12-inch-square tiles and 10% waste, buy at least 132 tiles. If boxes contain 10 tiles, 14 boxes provide 140 tiles.
Practical tips
- Use 10% waste for many straight layouts; diagonal patterns or complicated rooms may need 15% or more.
- Subtract large areas that will not be tiled, but keep enough material for cuts.
- Confirm nominal versus actual tile dimensions and tiles per box.
Assumptions and limitations
The estimate is area-based and does not model grout-joint width or the exact cut layout. Box quantities always round up.
Frequently asked questions
Does grout spacing reduce the number of tiles?
Slightly, but the waste allowance normally covers that small difference for planning. A layout plan is better for precise counts.
Should I keep spare tile?
Keeping a few matching tiles helps with later repairs, especially when a product may be discontinued.