Pork Loin Roast Cook Time Per Pound
Pork Loin Roast runs roughly 29 min/lb at 300 °F / 150 °C. But that number is an average, not a law — see below.
The per-pound rule is wrong, and here is by how much
Everyone quotes a single figure. It cannot be right, because heat travels inward from the surface: what sets the time is thickness, and a heavier cut is mostly longer and wider rather than thicker.
On this cut the real spread is 0.52 h/lb at 2.5 lb down to 29 min/lb at 5 lb — a 7% difference. Plan a big one with the small-cut figure and you will be sitting around for hours; plan a small one with the big-cut figure and dinner is late.
Cook time by weight
| Weight | Total time | Time per pound | Full guide |
|---|---|---|---|
| 2.5 lb | 1h 17m | 0.52 h/lb | Timeline → |
| 3 lb | 1h 31m | 0.51 h/lb | Timeline → |
| 4 lb | 1h 58m | 29 min/lb | Timeline → |
| 5 lb | 2h 24m | 29 min/lb | Timeline → |
What actually changes the time more than weight
- Thickness and shape. A thick, square pork loin takes noticeably longer than a flat one of the same weight.
- Pit temperature. The single biggest lever. Running hotter cuts the time substantially — every guide on this site gives the exact figure per method.
- Lid discipline. Every peek costs you heat and time. This is the variable people underestimate most.
- Starting temperature. These figures assume fridge-cold. Meat left out for an hour first runs faster.
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Time is an estimate. Temperature is the truth.
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Instant-Read Digital Thermometer
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Per-pound times for other cuts
Download the printable temperature chart
Every temperature on this site on one page — beef, pork, poultry, seafood and low & slow, plus the carryover rule. Print it and tape it inside your grill lid.
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Frequently Asked Questions
How many hours per pound for pork loin?
About 29 min/lb at 300 °F for a typical 4 lb cut. Use the table rather than the single number: the figure drops as the cut gets bigger.
Why is hours-per-pound not a fixed number?
Heat travels inward from the surface, so what actually sets the cook time is how thick the meat is, not how heavy. Doubling the weight of a pork loin does not double its thickness — it mostly gets longer and wider. So a big one needs less time per pound than a small one: 0.52 h/lb at 2.5 lb versus 29 min/lb at 5 lb.
Can I trust per-pound maths to plan dinner?
Use it to know when to light the fire, never to know when to serve. Two cuts of identical weight can differ by hours depending on shape, fat content and how often the lid comes off. Budget spare time and hold it wrapped if it finishes early.