The length of time it takes to cook roast beef depends on the style of roast and to what level of doneness the cook desires; for example, a roast that takes 20 minutes per pound will cook in 50 minutes. Whether or not it is a bone-in or boneless roast also determines the cooking time.
Roasting beef is based on the amount of time per pound. Some examples include:
- Bottom round roast - a 2-1/2-lb. roast takes an hour and 15 minutes, or 30 minutes per pound, cooked at 325 degrees Fahrenheit to reach medium-rare, or an internal temperature of 145 F;
- Eye round roast - a 2 1/2-lb. roast takes between 1 1/2 and 2 hours, cooked at 325 F until it reaches medium-rare;
- Rib eye roast - a 2 1/2-lb. roast takes about 1 3/4 hours cooked at 350 F for medium rare.
Once removed from the oven after reaching the desired internal temperature, the roast should rest for 10 to 15 minutes before serving.