If you don't want joins your first border needs to have a few inches over 2 yards so you can cut the fabric lengthwise. Add the borders to the LONG sides first and then add the top and bottom. You will have a lot of fabric left over from this.
For the outside border you'll need 2 yards plus 6 inches. Again doing it this way there will a considerable amount left over.
To do pieced borders you will need considerably less. And my measurements are generous just incase your quilt is a little over 72" and the first border ends up being a little wider than 1 inch.