Crunch Tile Calculator
Tiles by the room, not by guesswork. Enter the floor, pick a tile size (or type your own), set the grout gap, and get the tile count two independent ways — by coverage and by the actual grid — plus boxes and cost with the standard 10% waste allowance built in.
How it works
Two methods, cross-checked. By coverage: room area ÷ one tile’s area, rounded up, then +10% for cuts and breakage. By grid: tiles along each wall = room side (in inches) ÷ (tile size + grout gap), rounded up per side, then multiplied — the count if you lay whole tiles and cut only at the edges. When the grid count is higher it is usually the honest one for small rooms and big tiles. Boxes round up from the coverage count, because stores sell whole boxes.
Formula & worked example
Formula: By coverage: room area ÷ one tile’s area, rounded up. By grid: each wall’s length in inches ÷ (tile size + grout gap), rounded up per side, then multiplied. Buy the coverage count plus a waste allowance (10% standard): ceil(count × 1.10), then divide by tiles per box and round up again.
Worked example: A 10 × 12 ft room (120 sq ft) with 12 × 12 in tiles: 120 tiles by coverage, and the grid with a 1/8 in grout gap agrees at 120 (10 across × 12 down). With 10% waste you buy 132 tiles — 14 boxes of 10, about $630 at $45 a box.
Frequently asked questions
How many tiles for a 10 × 12 ft room with 12-inch tiles?
The room is 120 sq ft and each 12 × 12 tile covers exactly 1 sq ft, so 120 tiles by coverage. Add the standard 10% waste allowance and you buy 132 tiles — 14 boxes of 10, about $630 at $45 a box. The grid method with a 1/8-inch grout gap also lands on 120 before waste (10 across × 12 down).
Why does the grid count differ from the coverage count?
Coverage assumes tiles can be cut and pieces reused anywhere; the grid counts whole tiles per row and column with grout gaps, rounding up on each side. Big tiles in small rooms make the grid count jump — a half-tile strip on two walls still consumes whole tiles unless offcuts fit elsewhere.
How much waste should I add?
10% for straight layouts in rectangular rooms, 15% for diagonal or large-format tile, 20% for herringbone and rooms with many corners. Breakage in transit and cutting mistakes are normal, and dye lots differ — running short mid-job is the expensive outcome.
Does the grout gap really change the count?
A little. Each tile effectively occupies tile size + gap, so a 12-inch tile on 1/8-inch grout covers a 12.125-inch module. On long walls that quietly removes a tile per row now and then — the grid count above includes it, the coverage count does not.
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