How long to cook a prime rib roast for Christmas
A bone-in rib roast takes 23 to 30 minutes per lb at 325°F, so a 6-lb roast needs about 2¼ to 3 hours. Here is every size and the temperature to pull it.
23 to 30 min per lb at 325°F (163°C) for a bone-in rib roast of 4 to 8 lb, so a 6-lb roast takes about 2¼ to 3 hours, to at least 145°F (63°C).
The time
USDA's holiday roasting chart gives a bone-in beef rib roast of 4 to 8 lb (1.8 to 3.6 kg) 23 to 30 minutes per pound in a 325°F oven. A boneless rib roast takes longer per pound, 39 to 43 minutes for a 4-lb roast, because heat moves more slowly through solid meat than along the bone.
Roast it uncovered on a rack in a shallow pan. A roast straight from the fridge sits at the slower end of the range, and so does a very thick one.
Times by size
Calculated from USDA's minutes per pound at 325°F:
| Roast | Weight | Time |
|---|---|---|
| Bone-in | 4 lb (1.8 kg) | 1½ to 2 hours |
| Bone-in | 5 lb (2.3 kg) | 1 hr 55 min to 2½ hours |
| Bone-in | 6 lb (2.7 kg) | 2¼ to 3 hours |
| Bone-in | 7 lb (3.2 kg) | 2 hr 40 min to 3½ hours |
| Bone-in | 8 lb (3.6 kg) | 3 hr 5 min to 4 hours |
| Boneless | 4 lb (1.8 kg) | 2 hr 35 min to 2 hr 50 min |
How to tell it is done
Use a food thermometer in the center of the roast, away from the bone. USDA's safe minimum for beef roasts is 145°F (63°C), measured before the meat leaves the oven, followed by a rest of at least 3 minutes. You can cook it further if you prefer it more done.
Start checking 30 minutes before the shortest time in the table, then every 15 minutes.
Rest it, loosely covered with foil, before carving. Resting longer than 3 minutes is fine and gives you time to finish the sides in the oven.
Work it back
Christmas dinner at 3:00 p.m. on Friday, 25 December, with a 6-lb bone-in roast:
| Clock | Step |
|---|---|
| 11:00 a.m. | Preheat the oven to 325°F. |
| 11:20 a.m. | Roast in the oven. That allows the full 3 hours. |
| 1:05 p.m. | Start checking the temperature. |
| 2:20 p.m. | Roast out at 145°F or your preferred doneness. Rest under foil. |
| 2:40 p.m. | Carve. |
| 3:00 p.m. | Eat. |
Buying ahead? Fresh beef keeps 3 to 5 days in the fridge, so a roast bought on Monday 21 December is fine for Christmas Day. Buy it earlier and freeze it, then thaw it in the fridge.
Other Christmas roasts
Not a prime rib table this year? USDA's holiday chart covers the other big roasts too. All of these are done at a minimum of 145°F (63°C), followed by a rest of at least 3 minutes.
| Roast | Weight | Oven | Time |
|---|---|---|---|
| Beef tenderloin, whole | 4 to 6 lb | 425°F (218°C) | 45 to 60 min in total |
| Beef tenderloin, half | 2 to 3 lb | 425°F (218°C) | 35 to 45 min in total |
| Beef eye round | 2 to 3 lb | 325°F (163°C) | 20 to 22 min per lb |
| Leg of lamb, bone-in or boneless | 4 to 9 lb | 325°F (163°C) | 20 to 26 min per lb |
| Pork crown roast | 6 to 10 lb | 325°F (163°C) | 20 to 25 min per lb |
| Pork loin, bone-in | 3 to 5 lb | 325°F (163°C) | 20 to 25 min per lb |
Tenderloin is the quick one: an hour at most, so it can go in while a ham or turkey rests.
Food safety
- USDA does not recommend roasting at oven temperatures below 325°F, because the meat can sit too long in the 40°F to 140°F danger zone.
- Leftover roast beef: refrigerate within 2 hours, in shallow containers.
Sources
- USDA Food Safety and Inspection Service, Roasting Those "Other" Holiday Meats (holiday meat roasting chart, safe temperatures, storage of fresh meat).
