When it comes to making a bed scarf, the amount of fabric you need will depend on the size of the bed you're working with. For a standard twin bed, you'll need approximately 1 1/2 yards of fabric. For a full-size bed, you'll need approximately 2 yards of fabric. For a queen-size bed, you'll need approximately 2 1/2 yards of fabric. And for a king-size bed, you'll need approximately 3 yards of fabric.
Keep in mind, these are just general guidelines. The best way to ensure you have enough fabric is to measure your bed and then add a few inches to account for any shrinkage that may occur during the washing and drying process.