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Prime Rib Cooking Time Calculator

Prime rib, also known as standing rib roast, is the ultimate holiday centerpiece. This well-marbled cut comes from the primal rib section and delivers exceptional flavor and tenderness when cooked low and slow.

Prime Rib Cooking Calculator
Enter your prime rib details to calculate cooking time

Enter the weight of your prime rib

Estimated Cooking Time

3h 20m

(200 minutes total)

Internal Temp

160°F

Resting Time

20 min

USDA Safe Temperature: The USDA recommends cooking beef to an internal temperature of at least 160°F for food safety. Always use a meat thermometer to verify.

Pro Tips for Prime Rib

  • 1Remove from fridge 2 hours before cooking for even results
  • 2Season generously with salt the night before for deeper flavor
  • 3Use the reverse sear method: roast low (250°F), then sear at 500°F
  • 4Carryover cooking adds 5-10°F, remove 5-10° below target temp
  • 5Request 'first cut' from butcher for more meat, less fat
  • 6Calculate 1 rib per 2 guests, or 1 pound per person

Frequently Asked Questions

How long to cook prime rib at 250 degrees?
At 250°F, prime rib takes approximately 25-30 minutes per pound for medium-rare. A 6 lb roast would take about 2.5-3 hours. This low-and-slow method produces incredibly tender results.
How long to cook a 5 lb prime rib?
A 5 lb prime rib at 325°F takes approximately 1 hour 15 minutes for rare, 1 hour 30 minutes for medium-rare, or 1 hour 45 minutes for medium. Always use a meat thermometer.
Should I sear prime rib before or after roasting?
Both methods work. Traditional method sears first then roasts. Reverse sear (roast first, sear last) gives you more control and a better crust. Most chefs prefer the reverse sear method.
How much prime rib per person?
Plan for 1 pound of bone-in prime rib per person (or 2 people per rib bone). For boneless, plan 8-10 ounces per person. Always buy slightly more than you think you need.

Last updated: December 2025