782 plus 5.0% divided by sq ft in box rounded up to nearest box..

More if you are using multiple widths or have a weird shaped room. I have hardwood and tile everywhere because I have allergies and a dog. A lot of people prefer carpeting in bedrooms because it is quieter (especially helpful when they are on the second floor) and warmer on bare feet.

We always figure 10%. There was a time 30 years ago when 5% did us well but today the coverages stated per bundle seem to come up a little short too often.