A beef roast is cooked in a 375 degrees Fahrenheit oven for 20 minutes per pound. The exact cooking time depends on the size of the roast. The roast is done when it reaches between 135 and 150 degrees Fahrenheit on a meat thermometer.
The cooking time for a beef roast depends on how well done you want the roast to be at serving time. The best indicator is a meat thermometer. For a medium-rare roast, the temperature should be 135 degrees Fahrenheit when it is removed from the oven and 145 degrees Fahrenheit after it rests. For a medium roast, the temperature should be 150 degrees Fahrenheit when it is removed from the oven and 160 degrees Fahrenheit after resting.
The cooking temperature and time also depends on the cut of the roast and if the bone is present. A standard rump roast is cooked at 325 degrees Fahrenheit for 20 minutes per pound, while a tenderloin roast is cooked at 425 degrees Fahrenheit for 20 to 25 minutes per pound. Be certain that the thermometer does not touch the bone when it is inserted into a bone-in roast.