Bake pork loin at 400°F for about 20–25 minutes per pound, until the center reaches 145°F. Let it rest 3 minutes before slicing. A 2-pound pork loin usually takes about 40–50 minutes.
How Long To Bake Pork Loin At 400: bake pork loin for about 20 to 25 minutes per pound, until the center reaches 145°F (63°C), then rest it for 3 minutes. For a 2 lb pork loin, that usually means 40 to 50 minutes.
Use a meat thermometer in the thickest part of the loin, not touching fat or pan. Pull it from the oven at 145°F, rest for 3 minutes, then slice. A 400°F oven gives faster browning than 350°F, so check early to avoid drying it out.
The Short Answer, With Numbers
Bake pork loin at 400°F for about 20 to 25 minutes per pound, then verify doneness with a thermometer. The target for pork loin is 145°F internal temperature, followed by a 3-minute rest.
| Food | Safe minimum internal temperature | Rest time |
|---|---|---|
| Beef, pork, veal and lamb – steaks, chops, roasts | 145°F (63°C) | 3 minutes |
| Leftovers, reheated | 165°F (74°C) | None |
400°F Pork Loin Timing Guide
For a boneless pork loin roast at 400°F, use 20 to 25 minutes per pound as the planning range. A 2 lb roast usually takes 40 to 50 minutes. A 3 lb roast usually takes 60 to 75 minutes.
A 4 lb pork loin usually needs 80 to 100 minutes at 400°F. Start checking early, because shape matters. A long, narrow roast cooks faster than a short, thick roast of the same weight.
Example: for a 3 lb boneless pork loin, multiply 3 by 20 to 25. That gives 60 to 75 minutes. Begin checking the center around 55 to 60 minutes so you do not overshoot.
Example: for a 2.5 lb pork loin, multiply 2.5 by 20 to 25. That gives 50 to 62.5 minutes. Check at about 48 to 50 minutes, then continue in 5-minute increments if needed.
The number that matters is not the clock; it is 145°F in the thickest part. Insert the thermometer from the side if possible, aiming for the center of the roast, not the pan or fat cap.
After the pork loin reaches 145°F, rest it for 3 minutes before slicing. During the rest, juices settle and the roast finishes safely according to the pork roast temperature rule.
When The Time Changes
If the pork loin is tied, stuffed, unusually thick, or started very cold, expect the longer end of the range. If it is thin, evenly shaped, or cut into two smaller roasts, expect the shorter end.
A seared pork loin still needs the same internal target. Searing may add browning, but it does not replace thermometer checking. Count oven time from when the roast goes into the 400°F oven.
If reheating cooked pork loin leftovers, the relevant target is different: reheat leftovers to 165°F. That is not the same as cooking a fresh pork loin roast to 145°F with a 3-minute rest.
Practical check points: 2 lb, check at 40 minutes; 3 lb, check at 55 to 60 minutes; 4 lb, check at 75 to 80 minutes. Pull only when the center reads 145°F, then rest 3 minutes.
Bake Time At 400
Bake pork loin at 400°F for about 20 to 25 minutes per pound, until the center reaches 145°F. Rest it for 3 minutes before slicing.
For most boneless pork loins, that means a 2 lb roast takes 40 to 50 minutes, a 3 lb roast takes 60 to 75 minutes, and a 4 lb roast takes 80 to 100 minutes.
| Pork loin weight | Estimated time at 400°F | Target internal temperature |
|---|---|---|
| 1.5 lb | 30 to 38 minutes | 145°F, then rest 3 minutes |
| 2 lb | 40 to 50 minutes | 145°F, then rest 3 minutes |
| 2.5 lb | 50 to 63 minutes | 145°F, then rest 3 minutes |
| 3 lb | 60 to 75 minutes | 145°F, then rest 3 minutes |
| 4 lb | 80 to 100 minutes | 145°F, then rest 3 minutes |
Worked Examples
A 2.25 lb pork loin at 400°F should take about 45 to 56 minutes. Start checking with a thermometer at the 42-minute mark, especially if the roast is narrow.
A 3.5 lb pork loin should take about 70 to 88 minutes. Check at 65 minutes, then every 5 to 8 minutes until the thickest center reads 145°F.
A long, skinny 3 lb loin may finish closer to 60 minutes. A short, thick 3 lb loin may need closer to 75 minutes, because thickness matters more than total weight.
Boneless vs. Bone-In
Most pork loin roasts sold in US supermarkets are boneless. For boneless pork loin at 400°F, use 20 to 25 minutes per pound as the main estimate.
If your pork loin is bone-in, plan on the upper end of the range. A 3 lb bone-in pork loin is more likely to take 70 to 80 minutes than 60 minutes.
Covered or Uncovered
Bake pork loin uncovered at 400°F for better browning. Covering traps steam and can soften the surface, especially if the roast was rubbed with oil, salt, garlic, or sugar.
If the outside is getting too dark before the center reaches 145°F, tent loosely with foil for the final 10 to 20 minutes. Do not wrap it tightly.
When to Start Checking
Start checking early: at 18 minutes per pound for small or narrow roasts, and at 20 minutes per pound for thicker roasts.
Insert the thermometer into the thickest part of the loin, not the end. Avoid touching the pan, fat cap, or stuffing. Pork loin is done when the center reaches 145°F.
After baking, rest the pork loin for 3 minutes. Slice across the grain into 1/4-inch to 1/2-inch slices for cleaner cuts and better texture.
Pork Loin Size Guide
At 400°F, boneless pork loin usually takes about 20 to 25 minutes per pound, but thickness matters more than weight. Pull it when the center reaches 145°F, then rest 3 minutes.
400°F Baking Times by Pork Loin Size
| Pork loin size | Typical shape | Estimated bake time at 400°F | Check temperature at |
|---|---|---|---|
| 1 lb | Small, narrow roast | 20 to 25 minutes | 18 minutes |
| 1 1/2 lb | Short roast | 30 to 38 minutes | 28 minutes |
| 2 lb | Common family-size loin | 40 to 50 minutes | 36 minutes |
| 2 1/2 lb | Thicker center-cut roast | 50 to 63 minutes | 46 minutes |
| 3 lb | Large boneless loin | 60 to 75 minutes | 55 minutes |
| 4 lb | Long, thick roast | 80 to 100 minutes | 72 minutes |
Example: a 2 lb pork loin at 400°F should start checking at 36 minutes. If it reads below 145°F in the center, return it to the oven and recheck every 5 minutes.
Example: a 3 lb pork loin may be done near 60 minutes if it is long and even. If it is a squat, thick roast, it may need closer to 75 minutes.
For a 4 lb pork loin, do not rely on the “per pound” number alone. A long roast may cook faster than expected, while a compact roast can lag by 15 to 20 minutes.
Thickness Changes the Clock
A pork loin that is 2 inches thick cooks much faster than one that is 3 1/2 inches thick, even if both weigh about 2 lb. Heat must reach the cold center, not just the surface.
If your pork loin is tied into a round shape, use the high end of the time range. If it is flattened or naturally oval, use the low end and start checking early.
A roast straight from the refrigerator often needs more time than one that sat at room temperature briefly while the oven preheated. The thermometer decides the final timing.
Bone-In, Stuffed, and Pan Crowding Notes
Bone-in pork loin can take about 5 to 10 minutes longer than a similar boneless roast at 400°F. Check near the bone and in the thickest center area.
Do not use this timing for stuffed pork loin. Stuffing changes heat flow and makes the center harder to judge. Use a thermometer in the stuffing and meat, not time alone.
If vegetables fill the pan tightly around the roast, add 5 to 15 minutes. Crowding blocks hot air and can slow browning and internal heating.
For sliced pork loin portions, timing drops sharply. Thick 1-inch slices may take about 12 to 18 minutes at 400°F, while a whole roast of the same total weight takes longer.
After baking, rest pork loin for 3 minutes once it reaches 145°F. Slice across the grain into 1/4-inch to 1/2-inch slices for the juiciest texture.
How To Bake It
Bake pork loin at 400°F until the thickest center reaches 145°F, then rest it 3 minutes. For most boneless pork loin roasts, plan on 18 to 25 minutes per pound.
400°F Pork Loin Timing
| Pork loin size | Estimated bake time at 400°F | When to start checking |
|---|---|---|
| 1 lb | 18 to 25 minutes | 15 minutes |
| 2 lb | 36 to 50 minutes | 32 minutes |
| 3 lb | 54 to 75 minutes | 48 minutes |
| 4 lb | 72 to 100 minutes | 65 minutes |
- 1. Heat the oven to 400°F. Place a rack in the center of the oven. Use a rimmed baking sheet, roasting pan, or oven-safe skillet. Line the pan with foil only if you still leave the pork exposed to dry heat.
- 2. Prep the pork loin. Pat the roast dry. Trim only thick surface fat, leaving about 1/8 inch if present. Rub with oil, then season heavily. For a 3 lb loin, use about 1 tablespoon kosher salt plus pepper, garlic, and herbs.
- 3. Position it correctly. Set the pork fat-side up if it has a fat cap. Keep the roast in one compact piece, not butterflied open. A long, narrow 2 lb loin may cook faster than a short, thick 2 lb loin.
- 4. Bake uncovered. Roast at 400°F. Use the table as a timing guide, not the final test. A 2 lb roast usually takes 36 to 50 minutes; a 3 lb roast usually takes 54 to 75 minutes.
- 5. Check the center temperature. Insert the thermometer into the thickest part from the side, avoiding the pan and any fat pocket. Pull the pork when the center reads 145°F.
- 6. Rest before slicing. Move the pork to a board and rest it 3 minutes. Do not skip this for a pork loin roast. Slice across the grain into 1/4- to 1/2-inch slices.
Worked Examples
Example 1: A 2 lb boneless pork loin at 400°F should be checked at 32 minutes. If it reads 136°F, return it to the oven and check again in 5 to 7 minutes.
Example 2: A 3 lb pork loin often lands near 60 to 65 minutes. Start checking at 48 minutes, because shape matters more than weight once the roast is thick.
Example 3: A 4 lb roast can take 72 to 100 minutes. If the outside is browning too fast before the center reaches 145°F, loosely tent the top with foil and keep baking.
Edge Cases
If the pork loin is tied, stuffed, or unusually thick, expect the high end of the range. Check early, then continue in short intervals so you do not overshoot the center.
If the roast is cut into two smaller pieces, time drops sharply. Two separate 1.5 lb pieces will usually cook closer to 27 to 38 minutes than one dense 3 lb roast.
If you sear before baking, the oven time may be shorter by 5 to 10 minutes. Still use 145°F in the thickest center plus a 3-minute rest as the doneness target.
Checking For Doneness
For pork loin, the doneness target is 145°F (63°C) in the thickest part, followed by a 3-minute rest. At 400°F, time estimates help, but the thermometer decides when it is done.
Start checking early. A 2 lb pork loin may reach 145°F faster than expected if it is narrow, while a 4 lb roast may need noticeably longer if it is thick through the center.
Where To Put The Thermometer
Insert an instant-read thermometer into the center of the thickest section. Push the probe in from the side when possible, aiming for the middle of the roast rather than the top surface.
Avoid touching the roasting pan, a fat cap, or any bone if present. Those areas can give a false reading. For an even pork loin, check 2 spots: the center and one end.
If the center reads 142°F but the end reads 150°F, keep cooking. The lowest correct reading controls doneness. Pork loin is done only when the thickest center reaches 145°F.
Worked Timing Checks At 400°F
Example 1: a 2 lb pork loin has baked for 35 minutes. The center reads 138°F. Return it to the oven and check again in 5 minutes, not 15, because it is close.
Example 2: a 3 lb pork loin reads 145°F in the center at 52 minutes. Remove it from the oven immediately and rest it for 3 minutes before slicing.
Example 3: a 4 lb pork loin reads 145°F at one end but 139°F in the center. Keep baking and recheck the center after 5 to 7 minutes.
| Thermometer Reading | What To Do |
|---|---|
| 130°F to 137°F | Continue baking; check again in about 8 to 10 minutes. |
| 138°F to 144°F | Continue baking; check again in about 5 minutes. |
| 145°F | Remove from oven and rest 3 minutes. |
| Above 145°F | Remove from oven; rest 3 minutes before slicing. |
Edge Cases That Change The Reading
A tied pork loin can cook unevenly if one end is thicker. Check the thickest tied section first. If that part is 145°F, the thinner end is usually already at or above target.
A stuffed pork loin is not covered by the plain pork-roast target. Use the applicable stuffed-meat guidance for safety; do not judge it by the pork loin alone.
If the roast was seared before baking, the outside may look done early. Browning is not doneness. A dark crust at 25 minutes can still hide a center below 145°F.
If juices run slightly pink, do not use color as the final test. Pork loin can be safe after reaching 145°F and resting 3 minutes, even if it is faintly rosy inside.
After the 3-minute rest, slice across the grain into 1/2-inch pieces for serving. If the center was verified at 145°F, the roast has met the USDA doneness target.
Resting Before Slicing
Rest pork loin for at least 3 minutes after it reaches 145°F in the thickest part. That 3-minute rest is part of the USDA safe minimum for pork roasts, including pork loin.
For best slicing, use 10 minutes for a small pork loin and 15 minutes for a larger roast. The extra time lets juices settle, so the cutting board does not get flooded.
Exact Rest Times By Pork Loin Size
| Pork loin size | Minimum safe rest | Best slicing rest |
|---|---|---|
| 1 to 1 1/2 lb | 3 minutes | 8 to 10 minutes |
| 2 to 3 lb | 3 minutes | 10 to 15 minutes |
| 4 to 5 lb | 3 minutes | 15 to 20 minutes |
A 2 1/2 lb pork loin baked at 400°F should be pulled when the center reads 145°F. Rest it 10 to 15 minutes, then slice across the grain into 1/2-inch pieces.
If you slice at the 3-minute mark, it is safe once it hit 145°F, but the slices will lose more juice. Use 3 minutes only when you need to serve immediately.
Do not tent tightly with foil. A tight wrap traps steam and softens the browned surface. Instead, lay foil loosely over the roast, leaving gaps at the sides.
For a crustier outside, rest the pork loin uncovered for the first 5 minutes. Then drape foil loosely if the kitchen is cool or the roast will sit longer than 10 minutes.
Worked Examples
Example 1: a 1 1/4 lb pork loin reaches 145°F after baking at 400°F. Rest 8 minutes, then cut into 1/2-inch slices. The center should be easier to cut without tearing.
Example 2: a 3 lb pork loin reaches 145°F. Rest 15 minutes before slicing. If serving on a platter, slice only half first and keep the rest whole to hold moisture.
Example 3: a 4 1/2 lb pork loin comes out at 145°F. Rest 20 minutes. Large roasts keep heat longer, so this longer pause improves texture without rushing the cut.
Use the thermometer before resting, not after guessing by time. Insert it into the thickest center section, avoiding fat seams and the pan surface.
If one end is thinner, check the thick center first. The thin end may look drier, so slice that end a little thicker, about 3/4 inch, and cut the juicier center 1/2 inch thick.
If the pork loin was stuffed, treat it as stuffed pork and cook it to 165°F with no rest time required for safety. Resting 10 to 15 minutes still helps it slice neatly.
If the roast contains a pocket of seasoning, fruit, or breadcrumb filling, check the filling too. The center of that filling must meet the stuffed-pork requirement.
Rest on a warm plate or cutting board with a juice groove. Do not rest in the hot baking pan, because the pan can keep cooking the bottom and make the ends drier.
Slice with a sharp knife across the grain. For sandwiches, use 1/4-inch slices after a full 15-minute rest. For dinner portions, 1/2-inch slices hold together better.
If juices run heavily when you make the first cut, stop slicing and wait 5 more minutes. That short pause can save the remaining roast from drying out on the board.
Frequently Asked Questions
How long do you bake pork loin at 400°F?
Bake pork loin at 400°F for about 20 to 25 minutes per pound, then check the thickest part with a food thermometer. It is done at 145°F, followed by a 3-minute rest. A 2-pound pork loin usually takes about 40 to 50 minutes.
How long does a 3-pound pork loin take at 400°F?
A 3-pound pork loin usually takes about 60 to 75 minutes at 400°F. Start checking around 55 minutes because oven accuracy and roast shape matter. Remove it when the center reaches 145°F, then let it rest for 3 minutes before slicing.
Should I cover pork loin when baking at 400°F?
Bake pork loin uncovered at 400°F if you want a browned outside. If the surface gets too dark before the center reaches 145°F, loosely tent it with foil. Rest the roast for 3 minutes after baking so juices settle before cutting.
What temperature should pork loin be after baking?
Pork loin, as a pork roast, should reach 145°F in the thickest part. Use an instant-read thermometer, not color, to judge doneness. After it reaches 145°F, let it rest for 3 minutes before slicing and serving.
How do I keep pork loin juicy at 400°F?
Do not bake pork loin past the target temperature. Start checking early, especially near 20 minutes per pound, and pull it at 145°F. Let it rest for 3 minutes before slicing. Cutting immediately can release more juices onto the board.
