How this calculator works
The calculator multiplies room length by width and adds extra areas. It applies waste allowance for ordering. Square yards are order area divided by 9. Roll length is order area divided by roll width, and padding rolls are estimated from order area divided by padding roll coverage.
Example: a 20 ft by 15 ft room plus 30 square feet of extra area totals 330 square feet. With 10% waste, the order area is 363 square feet, or 40.3 square yards. With a 12 ft roll, the estimate is 30.3 linear feet.