How long to smoke pork loin at 250°F

Work backwards from the long end. To serve a 4 lb pork loin at 6pm on a Saturday, light the smoker around Saturday 2:51pm — 3h 9m earlier. Every other weight is in the table below.

That asymmetry is deliberate. Finished barbecue sits in a cooler for hours and arguably improves; an unfinished one at dinner time is not a problem you can solve. Being early is recoverable, being late is not.

The smoker calculator turns your own serve time into a clock time, and handles weights and temperatures between the ones charted here.

The same pork loin can finish hours apart between cooks. Grade, fat, airflow, ambient temperature and how often the lid comes off all move the number, and a calculator can see none of them.

So the figures above are a window, not a prediction. A page that told you “2h 48m exactly” would feel more precise and be less true.

One thing worth being straight about: no institution publishes an hours-per-pound smoking rate for pork loin. USDA publishes safe internal temperatures, which are cited below, and a per-pound estimate for whole turkey — but not for this cut. The rate above is long-standing barbecue convention rather than a figure you can go and check, and the window is wide because that is the honest width.

Pull between 145–150°F internal. The USDA safe minimum for this cut is 145°F, which is a food-safety floor rather than a target.

Not a low-and-slow cut. Pull at 145°F and rest — every degree past that costs moisture.

That window is an internal temperature, and it is not what the lid gauge shows — a dome thermometer reads the air under the lid, not the centre of the meat. Hitting a 5°F window means measuring the meat itself, which is what an instant-read probe is for.

Safe minimums from the USDA FSIS Safe Minimum Internal Temperature Chart.

On a pellet grill at 250°F, this cook burns roughly 2–4.2 lb of pellets — so have a 20 lb bag on hand. Cold and windy days push that higher.

For an offset or a charcoal cooker there is no figure here, and that is on purpose. Consumption depends on firebox size, wood species, split moisture and how the pit is run, and a number would be a guess wearing an estimate’s clothes.

That fits a single load on any of the grills we compare, whose published hoppers start at 13.5 lb. Longer cooks are where that stops being true. The pellet grill comparison has the capacities.