It is not clear what is meant by an "18x18 square feet" tile. 18ft * 18 ft = 324 square feet, so that one tile will be more than enough. An 18 inch by 18 inch tile cannot be a 18x18 square feet tile.
2.25 square feet
1.78 sq feet per tile.
Multiply the two dimensions to get the area. The calculation will give you 2.25 square feet per tile for a total of 1,305 square feet.
There are 144 square inches in a square foot. In this case the calculation gives you 2.25 square feet.
This tile has an area of 1 ft2.
A square 20-inch tile is 2.78 square feet.
3.5555 square feet.
4.694 square feet.
18 in/12 in/ft = 1.5 feet 1.5 x 1.5 = 2.25 sq ft per tile 130 sq ft/2.25 sg ft/tile = 58 tiles
2.007 sq ft
18 inches = 1.5 foot18" x 18" = 1.5-ft x 1.5-ft = 2.25 square feet