Why the pull temperature matters more than the clock
Carryover cooking happens because the outer layers of a roast are hotter than the center when it comes out of the oven, and heat keeps migrating inward during the rest even though the oven is off. The bigger and denser the roast, the more heat is stored in those outer layers — which is why a prime rib, one of the largest single cuts most home cooks roast, can rise 5-10°F or more after it's pulled, noticeably more than a steak or a smaller roast would. Pulling at your final target temperature almost guarantees overshooting into the next doneness level up by the time you carve it. Pulling 8°F below target and letting the rest do the rest of the work is what actually lands you on the doneness you wanted.
Why the estimated time is only a planning number
Roasting time depends on more than weight and doneness — how cold the roast was going in, how accurate your oven's actual temperature is, the roast's exact shape and bone structure, and even your altitude all shift the real time meaningfully. Use the estimate to plan when to start (and when to begin checking), but let a thermometer make the actual call on when it comes out — start probing the thickest part, away from bone, at least 30-45 minutes before the estimated time so you don't get caught off guard by a roast that finishes early.
Resting is not optional
Beyond finishing the carryover rise, resting a roast this size for a full 20-30 minutes (tented loosely with foil) lets the juices redistribute through the meat instead of running out onto the cutting board the moment you slice in — skipping the rest undoes a meaningful amount of the care that went into getting the temperature right in the first place.
FAQ
Does bone-in vs. boneless change the numbers? Bone-in roasts insulate the meat near the bone slightly and are traditionally considered a touch more forgiving, but the per-pound time and pull temperatures here work as a reasonable estimate for either — always confirm with a thermometer in the thickest part of the meat itself, not near the bone.
What if I'm using the reverse-sear or "500-then-off" method instead? Those methods use a different heat profile than a steady 325°F roast, so this time estimate won't apply directly — but the pull temperatures and carryover logic are still the right numbers to target regardless of method.