Tile Calculator
Area to tile, the size of your tile, and the grout joint you plan to leave — from those three facts this tool derives how much floor each tile really occupies, then counts tiles, waste, and whole boxes.
Area, tile, and joint
Example: 100 sq ft of 12 × 12 in tile with a ¼ in joint and 10% waste → 106 tiles (11 boxes of 10).
Tile counts here are purchasing math only — waterproofing, substrate flatness, and structural or permit questions call for a licensed professional.
The tile-plus-joint footprint
Each installed tile occupies
(tile width + gap) × (tile height + gap) ÷ 144 square feet. For the worked bathroom:
a 12 in tile with a ¼ in joint claims 1.04 sq ft, so 100 sq ft needs
95.96 tiles net — against exactly 100 tiles if the same floor were
butt-jointed. Waste brings it to 105.56, purchased as
11 boxes of 10 (106
tiles rounded alone) with 4.44 tiles spare. Build-time engine output, same code
as the form above.
Frequently asked questions
Why does a wider grout joint mean FEWER tiles?
Each installed tile claims its own face plus half the joint on every side — effectively (width + gap) × (height + gap) of floor. A wider joint makes every tile account for more area, so the count drops. Small effect on big tiles, real effect on mosaics.
What grout gap should I enter?
Whatever your layout calls for: rectified tiles are often set at 1/16 to 1/8 in, standard pressed tiles commonly 1/8 to 1/4 in. Enter 0 for a butt-joint look. The tile box or your tile setter is the authority — the field takes any value up to 2 inches.
How much cutting waste for tile?
The 10% default convention suits straight layouts in simple rooms. Diagonal sets, patterns that must line up, many corners, or large-format tile that cracks on the last cut all justify 15%. Dye lots vary between orders, so buying enough up front matters more with tile than most materials.
The box count only appears when I fill in tiles per box — why?
Tile cartons range from a handful of large-format pieces to dozens of mosaics sheets, so no built-in box size would be honest. With the field blank you get a whole-tile count; add your carton’s count and the tool rolls it into boxes and, with a price, a cost.
Calculations never leave your browser. The full estimation pipeline — and why waste precedes packaging — is on the methodology page.