Enter your prime rib weight (in pounds), choose between bone-in or boneless, and select your preferred doneness level to get the recommended cooking time and oven temperature. You'll also see the target internal temperature to pull your roast at for perfect results every time.
Total Cooking Time
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Cook Time (Hours & Minutes)
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Oven Temperature
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Target Internal Temperature
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Resting Time
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Pull from Oven At
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The general rule is 15–20 minutes per pound for bone-in roasts and 12–15 minutes per pound for boneless, at 325°F. The exact time depends on your desired doneness — rare needs less time, well done requires more. Always use a meat thermometer to confirm internal temperature rather than relying solely on time.
Most recipes recommend roasting prime rib at 325°F (163°C) for even, controlled cooking. Some methods start with a high-heat sear at 450–500°F for 15–20 minutes to develop a crust, then reduce to 325°F for the remainder. This calculator uses the standard 325°F roasting method.
Medium rare prime rib has a target internal temperature of 130–135°F (54–57°C). You should pull the roast from the oven at about 125°F because the internal temperature will continue to rise 5–10 degrees during resting.
Yes, bone-in prime rib generally takes about 10–15% longer than a boneless roast of the same weight. The bones act as insulators, slowing heat penetration toward the center of the meat. However, many chefs prefer bone-in for flavor and moisture.
Prime rib should rest for at least 20–30 minutes after removing it from the oven. Larger roasts (8+ lbs) benefit from up to 30 minutes of rest. Resting allows the juices to redistribute throughout the meat, resulting in a more flavorful and juicy slice.
Rare: 120–125°F; Medium Rare: 130–135°F; Medium: 140–145°F; Well Done: 155–160°F. Always pull the roast 5–10 degrees before your target temperature, as carryover cooking during the rest period will bring it to the final desired temperature.
No — prime rib should be roasted uncovered to allow the exterior to develop a flavorful crust. However, you should tent it loosely with aluminum foil during the resting period to retain warmth without trapping steam, which would soften the crust.
Yes, it's recommended to let your prime rib sit at room temperature for 1–2 hours before roasting. This promotes more even cooking from edge to center. A cold roast straight from the refrigerator will cook unevenly, leaving the outside overdone while the center is still undercooked.