Tile Calculator — Free Online Tool
Tile math punishes guesswork: too few and you're hunting a discontinued dye lot; too many and you've paid for boxes that sit in the garage forever. This tile calculator converts your area and tile size into an exact tile count with a proper waste allowance.
What is the Tile Calculator?
The core calculation is area divided by tile area — a 12×12 tile covers exactly 1 square foot, so a 100 sq ft floor needs 100 tiles before waste. The waste factor is what separates pros from DIY disasters: 10% is the minimum for straight layouts, 15% for diagonal or brick patterns, and more for rooms with lots of cuts around toilets, vents, and doorways.
Buy all your tile from the same dye lot (check the box codes) — shade varies between production runs, and it's the #1 cause of “why does this patch look different.” Keep one full spare box after the job; if a tile cracks in five years, matching it then is nearly impossible. This tile calculator rounds up to whole tiles and applies your waste percentage on top, so the number it gives is the number to buy.
How to use this calculator
- Measure the length and width of the area in feet.
- Enter your tile size in inches (e.g. 12 × 12).
- Choose a waste percentage (10% straight, 15% diagonal).
- Click Calculate Tiles and check that all boxes share one dye lot.
Formula
Frequently asked questions
Is 10% waste enough for tile?
For straight grid layouts, yes. Use 15% for diagonal, herringbone, or brick patterns, and more for cut-heavy rooms. This tile calculator lets you set it.
What is a dye lot and why does it matter?
Tiles are fired in batches; shade varies slightly between batches. Mixing lots can leave visible patches — always buy one lot.
How many 12x12 tiles cover one square foot?
Exactly one — a 12×12 tile is 144 square inches, which equals one square foot.
Should I include grout lines in the tile size?
No — use the tile's nominal size. The waste allowance absorbs grout-gap differences.