In purely mathematical terms you would need a piece of carpet 12'w X 31' 3"l
This is assuming that the room is square (they almost never are), the carpet is at least 12' wide (it often isn't :-), that the factory edges can be joined perfectly to make acceptable seams (they seldom can be) and that there is no pattern that has to be matched
A professional measuring the room should estimate the minimum amount of (solid color) carpet needed at 12'w X 32'3" to allow for seams. Pattern carpet would require additional material to allow for matching
169 square feet
You need 7200 square feet of carpet in this case.
You would need 20 square yards of carpet which is 180 square feet.
224 square feet.
13-ft x 16-ft = 208 square feet
You need a price for the carpet, per square foot, to find the answer.
169 square feet
You will need: 12*24 = 288 square feet
You need 7200 square feet of carpet in this case.
800 square feet
You will need a minimum of 16 square feet of carpet to cover that area.
You would need 20 square yards of carpet which is 180 square feet.
224 square feet.
13-ft x 16-ft = 208 square feet
340sq feet.
The square footage of a 12 x 12 room is 144 feet. Most carpet comes in 12 foot width or wider. If it is 12 foot wide you just need a 12 foot piece off the roll. If the carpet is wider, you still have to buy that width and will have some waste.
120 square feet