Plan lamb roasts by the clock and finish them by thermometer: pick a cut, enter the weight, choose doneness, and get oven time, pull temperature, rest time and a serve-time plan — all from USDA safety temps.
| Cut | USDA minimum internal temp | Rest |
|---|---|---|
| Lamb roasts, steaks, chops (whole cuts) | 145°F (63°C) | 3 min minimum |
| Ground lamb (patties, kebabs, meatballs) | 160°F (71°C), no pink | 3–5 min |
| Danger zone | 40°F – 140°F | max 2 hr (1 hr above 90°F air) |
Doneness below 145°F (rare, medium-rare) is a personal-risk choice: the USDA does not recommend it. The calculator flags any target under 145°F.
| Cut | Oven | Time | Example |
|---|---|---|---|
| Leg, bone-in | 325°F | 25–32 min/lb (mid 28) | 5 lb → 2 hr 5 min – 2 hr 40 min |
| Leg, boneless (rolled) | 325°F | 22–28 min/lb (mid 25) | 4 lb → 1 hr 28 min – 1 hr 52 min |
| Shoulder, to medium | 325°F | 30–40 min/lb (mid 35) | 4 lb → 2 hr – 2 hr 40 min |
| Shoulder, pulled | 300°F | 75–105 min/lb (mid 90) | 5 lb → 6 hr 15 min – 8 hr 45 min |
| Rack | 450°F | 15–25 min total (mid 20) | — |
| Loin roast | 425°F | 12–16 min/lb (mid 14) | 2 lb → 24–32 min |
| Chops, 1 in thick | 400°F | 8–14 min total (mid 11) | after 1–2 min sear/side |
| Shank, braised | 325°F | 75–105 min/lb (mid 90) | 1.5 lb → ~2 hr 15 min |
| Ground patties, ½ in | 400°F | 10–14 min total (mid 12) | to 160°F, no pink |
| Doneness | Serve target | Pull: large roasts | Pull: chops / rack |
|---|---|---|---|
| Rare | 125°F (52°C) | 118°F | 120°F |
| Medium-rare | 135°F (57°C) | 128°F | 130°F |
| Medium | 145°F (63°C) | 138°F | 140°F |
| Medium-well | 150°F (66°C) | 143°F | 145°F |
| Well-done | 160°F (71°C) | 153°F | 155°F |
| Ground lamb (always) | 160°F (71°C) | 160°F — no carryover credit | |
Pull = target minus carryover (≈7°F for large roasts, ≈5°F for chops and rack). Ground lamb must hit 160°F in the center with no pink.
About 2 hours 20 minutes at medium-rare: plan 25 to 32 minutes per pound, with 28 minutes per pound as the midpoint, so 5 × 28 = 140 minutes = 2 hr 20 min. The full range for a 5 lb bone-in leg is 2 hr 5 min to 2 hr 40 min. Rest it 15 to 20 minutes tented in foil, and always confirm 135°F on a thermometer for medium-rare.
Plan 25 to 32 minutes per pound for a bone-in leg at 325°F, with 28 minutes per pound as the planning midpoint. A boneless rolled leg cooks a little faster: 22 to 28 minutes per pound, midpoint 25. Aim for the low end of the range for rarer doneness and the high end for more done, then verify with a thermometer.
USDA: 145°F with a 3-minute rest for whole cuts — roasts, steaks and chops. Ground lamb must reach 160°F all the way through, with no pink. These are food-safety facts from USDA FSIS, not medical advice.
Many cooks do, but be honest about it: 135°F is below the USDA minimum of 145°F for whole cuts, so it is a personal-risk choice, not the official recommendation. If you choose it, pull the roast at about 128°F, rest 15 to 20 minutes, and carryover of roughly 7°F brings it to 135°F. Use a thermometer and buy from a trusted source.
135°F internal after resting. Because large roasts climb about 7°F during the rest (small cuts like chops about 5°F), pull a leg or shoulder roast at about 128°F and chops or a rack at about 130°F. The pull temperature is always a few degrees below the target — that is carryover cooking, not a mistake.
About 30 to 40 minutes per pound at 325°F, midpoint 35, for a shoulder roasted to medium (145°F). A 4 lb shoulder lands around 2 hr 20 min. For pull-apart shoulder, go low and slow instead: 75 to 105 minutes per pound at 300°F until 195 to 205°F internal, about 7 hr 30 min for a 5 lb shoulder.
About 15 to 25 minutes total at 450°F, midpoint 20 minutes — racks are small (1 to 1.75 lb), so time barely scales with weight. Pull at about 130°F for medium-rare, rest 8 to 10 minutes, and it lands at 135°F.
After a 1 to 2 minute sear per side, about 8 to 14 minutes at 400°F for 1-inch chops, midpoint 11 minutes. Scale by thickness: a 1.5-inch chop needs about 12 to 21 minutes. Pull at 5°F below your target (130°F for medium-rare) and rest 5 to 10 minutes.
Large roasts: 15 to 20 minutes tented in foil. Loin roast: 10 to 15 minutes. Rack: 8 to 10 minutes. Chops: 5 to 10 minutes. Ground lamb patties: 3 to 5 minutes. USDA requires a minimum 3-minute rest for whole cuts — resting lets carryover finish the cook and juices redistribute.
Yes — about 10 to 15% longer. Bone slows heat penetration, so a bone-in leg needs 25 to 32 minutes per pound at 325°F versus 22 to 28 for boneless rolled. A 5 lb bone-in leg lands around 2 hr 20 min while a 5 lb boneless leg lands around 2 hr 5 min.
40°F to 140°F. Do not leave raw or cooked lamb in this range for more than 2 hours (1 hour when the air is above 90°F). This 2-hour rule covers resting, serving, marinating and leftovers alike.
No — this tool is lamb only. Each protein has its own time-and-temperature curves and USDA targets, so one tool per protein keeps the math honest. For chicken use our chicken cook time calculator, for pork our pork cook time calculator, for salmon our salmon cook time calculator, and for turkey sizing and thaw planning our turkey size calculator.
Use the boneless rates: 22 to 28 minutes per pound at 325°F, midpoint 25. A tied, uniform roll cooks evenly like a boneless roast. If the roll is very thick (over 5 inches across), plan toward the high end of the range and verify the center with a thermometer.
Work backward from the long end: about 2 hr 40 min of cook time plus 20 minutes of rest plus 20 minutes of prep means starting around 2:40 PM for a 6 PM serve. Finishing early is safe — a rested leg holds tented in foil for up to 30 minutes — so use the serve-time planner above and start from the high end.
One tool per protein: chicken, pork, salmon and turkey each have their own time-and-temperature math. This page is lamb only.