A full prime rib roast, also called a standing rib roast, has seven ribs and weighs usually between 15 and 19 pounds. This whole roast provides enough meat to feed a group of 14 or more, depending on whether or not they are big eaters.
The term “standing” means that the roast can stand by itself when the bones are included. A full rib roast starts from the seventh rib at the shoulder of the steer and goes back to the thirteenth or last rib at the loin. This is the same piece of meat that the rib-eye and rib steak are cut from. The only difference is, the rib steak has the bone in and the rib-eye does not.
A good rule of thumb when you are wanting to figure out exactly how much prime rib you will need, simply figure one rib for every two people which is a generous serving. So, if you plan to serve:
- six (6) people – three (3) rib roast
- eight (8) people – four (4) rib roast
- ten (10) people – five (5) rib roast
- twelve (12) people – six (6) rib roast
- fourteen (14) people – seven (7) rib roast
According to some, a prime rib roast should be no smaller than three ribs. Anything less than 3 ribs is not a roast but a thick steak and should be treated as such.