Prime Rib Cooking TimeCalculator
How long to roast a rib roast, eye round or beef tenderloin, and when to put it in the oven for your dinner time. Every number comes from the USDA roasting chart.
- Bone-in and boneless rib roast
- Minutes per pound at 325°F
- Start time for your dinner
- USDA sources shown
Your holiday roast
Free, instant, nothing is stored
More options
USDA times are approximate. Always check with a food thermometer. Not tested in our kitchen.
Your estimate
Pick your cut and enter its weight, then press Calculate.
About this prime rib cooking time calculator
This prime rib cooking time calculator multiplies your roast’s weight by the minutes per pound in the USDA holiday meat roasting chart. You pick the cut, enter the weight, and it gives a time range. Add your dinner time and it gives a window for when to put the roast in. The chart is on the USDA Food Safety and Inspection Service page Roasting Those “Other” Holiday Meats, where USDA calls the times approximate and meant for meal planning.
USDA’s chart calls the cut a “rib roast.” Many stores sell the same cut as prime rib. The word “prime” here is the name of the cut on the menu, and USDA’s chart does not mention the grade of beef.
USDA roasting times for beef
USDA says to cook raw beef roasts to at least 145°F, measured with a food thermometer, before taking the meat out of the oven, then rest it for at least 3 minutes before carving. It says some people choose higher temperatures for personal preference.
| Cut | Weight (lb) | Oven | Time |
|---|---|---|---|
| Rib roast, bone in | 4 to 8 | 325°F | 23 to 30 min per lb |
| Rib roast, boneless | 4 | 325°F | 39 to 43 min per lb |
| Eye round roast | 2 to 3 | 325°F | 20 to 22 min per lb |
| Tenderloin roast, whole | 4 to 6 | 425°F | 45 to 60 min total |
| Tenderloin roast, half | 2 to 3 | 425°F | 35 to 45 min total |
USDA gives no per-pound time for tenderloin. It lists total minutes at 425°F, so the calculator shows those as they are. It also explains why boneless takes longer per pound: boned and rolled meats need more time than bone-in cuts, because the heat has farther to go through solid meat.
What the calculator gives for common roasts
These rows are the calculator’s own arithmetic, the USDA minutes per pound times the weight. I have not cooked each one.
| Roast | Weight | Minutes per lb | Time at 325°F |
|---|---|---|---|
| Rib roast, bone in | 4 pounds | 23 to 30 | 1 h 32 min to 2 h |
| Rib roast, bone in | 6 pounds | 23 to 30 | 2 h 18 min to 3 h |
| Rib roast, bone in | 8 pounds | 23 to 30 | 3 h 4 min to 4 h |
| Rib roast, boneless | 4 pounds | 39 to 43 | 2 h 36 min to 2 h 52 min |
| Eye round roast | 3 pounds | 20 to 22 | 1 h to 1 h 6 min |
Why USDA says not to go below 325°F
USDA says roasting at about 325°F keeps meat tender and cuts down moisture loss. It does not recommend an oven temperature below 325°F, because meat could spend too long between 40°F and 140°F, the range where bacteria multiply fastest. If you plan a low-temperature roast, this calculator’s times do not apply and USDA gives no chart for it.
Limits of this calculator
- Weight ranges. Each USDA row covers a weight range, and the boneless rib roast row lists 4 pounds only. Outside the range, the calculator still multiplies but warns you.
- Cold start. USDA’s chart assumes beef cooked at refrigerator temperature, around 40°F. A roast left on the counter first will cook faster than the chart.
- No portion advice. The USDA page has no per-person amount for beef, so the calculator gives none.
- Not tested here. I have not roasted each cut in this tool, and the page says so.
Prime rib cooking time questions
How long do you cook prime rib per pound?
USDA lists 23 to 30 minutes per pound for a bone-in rib roast of 4 to 8 pounds at 325°F, and 39 to 43 minutes per pound for a 4-pound boneless rib roast.
What temperature should prime rib be?
USDA’s minimum internal temperature for beef roasts is 145°F, measured with a food thermometer, followed by a rest of at least 3 minutes. Some cooks choose a higher temperature for taste.
Does a boneless rib roast take longer than bone-in?
Per pound, yes. USDA lists 39 to 43 minutes per pound for boneless and 23 to 30 for bone-in, and says boned and rolled meats need more time because heat takes longer to reach the center.
How long should a roast rest?
USDA says at least 3 minutes before carving.
How long do you cook a beef tenderloin?
USDA lists 45 to 60 minutes total for a whole 4 to 6 pound tenderloin and 35 to 45 minutes for a half of 2 to 3 pounds, both at 425°F.
Sources
All numbers: USDA FSIS, Roasting Those “Other” Holiday Meats (last updated 5 December 2024), read on 26 October 2026. The arithmetic is ours.