How to Use
Choose whether to enter room dimensions (length and width) or a known floor area.
For multiple rooms, switch to Multiple Rooms and add up to 5 areas.
Enter your tile dimensions in centimeters (or inches if using feet).
Set a waste percentage to cover cuts and breakage. 10 percent is standard, 15 percent for diagonal layouts.
Optionally enter grout line width, tiles per box, and price per box for full cost estimates.
Results update automatically as you type.
How the Tile Count Formula Works
The base calculation divides total room area by the area of one tile to get the minimum tiles required. When a grout line width is specified, that value is added to both the tile length and tile width before computing tile area, because each tile occupies slightly more space on the floor once the joint is included. The waste factor then inflates the count: tiles needed with waste equals the base count multiplied by (1 + waste percentage divided by 100), rounded up to the nearest whole tile. If you provide tiles per box, the box count is the tile total divided by tiles per box, again rounded up so you never arrive on site one tile short.
Example Calculation
- Room: 4 m x 3 m = 12 m² total area
- Tile: 30 cm x 30 cm = 0.09 m² per tile
- With 3 mm grout: effective tile = 30.3 cm x 30.3 cm = 0.0918 m² per tile
- Base tiles needed: ceil(12 / 0.0918) = 131 tiles
- With 10 percent waste: ceil(131 x 1.10) = 145 tiles
- Box of 6 tiles: ceil(145 / 6) = 25 boxes
- At $24 per box: 25 x $24 = $600 estimated cost
When to Increase Your Waste Percentage
- Diagonal or herringbone layout requires 15 percent minimum
- Large format tiles (60 cm or more) in irregular rooms
- Rooms with many obstacles such as pillars, alcoves, or fixtures
- Matching veined or patterned tiles where cuts must align
- Buying discontinued tiles where replacements may not be available later
Always Buy a Contingency Box
Even with waste factored in, reserve at least one extra box from the same batch for future repairs. Tile batches vary in shade between production runs, and a replacement bought later may not match your existing floor.
Metric vs. Imperial: Which to Use
Key Features
Multi Room Support
Add up to 5 rooms and get a single combined tile and cost estimate for the entire project.
Waste Allowance
Adjustable waste percentage accounts for cuts, breakage, and pattern matching. Defaults to 10 percent.
Grout Line Adjustment
Specify grout joint width to get accurate coverage based on the actual installed tile spacing.
Box and Cost Calculator
Enter tiles per box and price per box to instantly see how many boxes to buy and the total material cost.
Unit Flexibility
Switch between metric (meters and centimeters) and imperial (feet and inches) to match your project measurements.
Privacy
All calculations run entirely in your browser. No measurements or project data are sent to any server.
Frequently Asked Questions
What waste percentage should I use?
For straight grid layouts, 10 percent covers typical cuts and breakage. Diagonal or herringbone patterns generate more offcuts, so 15 percent is safer. Rooms with many obstacles like pillars or alcoves benefit from 15 to 20 percent.
Why add grout line width to the calculation?
Each tile occupies slightly more floor space once grout joints are included. The calculator adds grout width to both tile dimensions before computing coverage, so your tile count reflects actual installed spacing rather than tile size alone.
Does this account for pattern matching or feature tiles?
Pattern matching waste is not calculated automatically. Increase your waste percentage manually. Large format tiles with veined patterns often need 20 percent or more to avoid visible mismatches at joins.
Can I use this for wall tiles?
Enter wall height as length and wall width as width, or type the total wall area directly. The tile and box calculations work the same regardless of the surface being tiled.