Tile Calculators
Tile quantity is area divided by tile size and then rounded up twice — once for cuts, once for the box. Wet areas add waterproofing that is priced by the roll, not the square foot.
There are 2 calculators here: Kitchen Backsplash Tile Calculator (tile, thinset, grout and edge trim for a backsplash) and Shower Tile & Waterproofing Calculator (tile, thinset, grout and waterproofing for a shower).
They all work the same way: quantity first, then a waste allowance you can change, then a price built from verified figures and adjusted for your state. Cost is always a range rather than a single number, and every assumption behind it is printed on the page with its source and the date it was last checked.