Many charts give roasting times per pound of meat. However, these can be approximate only and should be used in estimating and planning cooking times, not in determining doneness.
Many factors other than weight and oven temperature determine cooking time:
- Temperature of the meat before roasting.
- Amount of fat cover (fat acts as an insulator).
- Bones (bones conduct heat faster than flesh, so boneless roasts cook more slowly than bone-in roasts of the same weight).
- Size, type, and contents of the oven.
- Number of times the oven door is opened.
- Shape of the cut (a flat or a long, thin cut cooks more quickly per pound than a round, compact cut).