First, find the square footage of an 16" x 16" tile. 16 x 16 = 256 square inches. There are 144 square inches in a square foot (12" x 12" = 144). So divide 256 by 144 to get the square feet per tile. 324 / 144 = 1.78 sq ft per tile.
You have 270 square feet, using tiles that are 1.78 sq ft each. 270 / 1.78 = 151.7 tiles.
Generally, you will want to add from 5% to 10% for waste, depending on your layout (is it one big room, or several smaller rooms with lots of cutting?) (are you doing a checkerboard pattern, running bond (brick), or diagonal?) and your skill level. If in doubt, add 10% to be safe.
152 tiles + 10% --- that's 152 x 1.1 = 166.9 tiles.
Tiles that are two feet on a side cover 4 square feet. 378 of them cover 1512 square feet.
76.6 tiles
67 tiles.
157 18 by 18 tiles are needed to cover 352 square feet.
You will need at least 67 tiles. This will cover 150.75 square feet.
Tiles that are two feet on a side cover 4 square feet. 378 of them cover 1512 square feet.
192 tiles
76.6 tiles
67 tiles.
190
Two tiles will suffice since they will cover 36 square feet.
Since a 12x12 tile is one square foot, then 38 12x12 tiles will cover 38 square feet.
500/1.78 = 281 tiles
start with 38 tiles.
157 18 by 18 tiles are needed to cover 352 square feet.
Each tile covers 4 square feet. You will need 24.75 tiles to cover the area.
You will need at least 67 tiles. This will cover 150.75 square feet.