THE NUMORIX GUIDE
How to use the Tile Calculator
Last reviewed September 14, 2026
What this calculator does
The engine calculates room area as room length x room width in square feet.
Formula and method
The engine calculates room area as room length x room width in square feet. It converts tile dimensions from inches to square feet with tile length x tile width / 144, increases room area by 1 + wastePercent / 100, rounds the tile count up to a whole tile, and rounds that count up again to whole boxes using tilesPerBox.
Variables and inputs
Enter room length and width in feet, tile length and width in inches, waste as a percentage, and the number of tiles in one box. The result includes base room area, area after waste, whole tiles, and whole boxes.
Worked example
For a 12 ft x 10 ft room and 12 in x 12 in tiles, room area is 120 sq ft and one tile is 12 x 12 / 144 = 1 sq ft. With 10% waste, required area is 120 x 1.10 = 132 sq ft, so the engine returns 132 tiles. At 20 tiles per box, boxes are ceil(132 / 20) = 7.
How to interpret the result
Waste increases the area used to determine the tile count, while boxes are rounded to packaging units. The result is a purchasing estimate for a rectangular room under the entered layout assumptions, not a cutting diagram.
Common mistakes to avoid
Use feet for the room and inches for the tile, enter 10 for 10% waste, and enter the package count rather than the square-foot coverage if the field asks for tiles per box. Confirm the box's actual coverage when the package is sold by area.
Assumptions and limitations
The engine does not model grout joints, room irregularities, pattern layout, tile orientation, cuts around fixtures, broken tiles, lot matching, or package coverage differences. A single percentage may not fit diagonal or complex layouts, and it does not separately reserve spare tiles for future repairs.