Updated 30 September 2026
A roast leg of lamb is one of the easiest joints to get right, as long as you know the cooking time for its weight and how pink you like it. This guide gives leg of lamb cooking times per kg, from pink to well done, with oven temperatures, a core-temperature guide and a slow-roast method for meat that falls off the bone.
Quick answer: roast at 220°C (200°C fan, gas 7) for 20 minutes, then at 180°C (160°C fan, gas 4) for 25 minutes per kg for pink, 30 minutes per kg for medium or 35–40 minutes per kg for well done. Rest for 20–30 minutes before carving.
Leg of lamb cooking times per kg
These times are for a bone-in leg, after an initial 20 minutes at 220°C (200°C fan).
| Doneness | Time per kg at 180°C (160°C fan) | Core temperature when you take it out | After resting |
|---|---|---|---|
| Pink (medium-rare) | 25 minutes per kg | 55–57°C | about 60°C |
| Medium | 30 minutes per kg | 60–62°C | about 65°C |
| Well done | 35–40 minutes per kg | 68–70°C | about 72°C |
Worked examples:
- 1kg leg of lamb: 20 minutes plus 25 minutes for pink, about 45 minutes in total. For medium, about 50 minutes.
- 2kg leg: 20 minutes plus 50 minutes for pink (1 hour 10 minutes), or 1 hour 20 minutes for medium.
- 2.5kg leg: 20 minutes plus about 1 hour 3 minutes for pink (about 1 hour 25 minutes), or 1 hour 35 minutes for medium.
Boneless and butterflied legs cook faster. For a boneless rolled leg, allow roughly 5 minutes per kg less. A butterflied leg is thin enough to roast at 220°C (200°C fan) for 25–35 minutes in total or to cook on the barbecue.
The core temperatures are a cook's guide to doneness. The Food Standards Agency says whole cuts of lamb can be served pink as long as the outside is properly cooked. Rolled or stuffed joints should be cooked until steaming hot all the way through with no pink meat.
How to roast a leg of lamb
- Bring it to room temperature. Take the lamb out of the fridge an hour before cooking.
- Heat the oven to 220°C (200°C fan, gas 7).
- Flavour it. Make 12–15 small, deep cuts all over the leg with a sharp knife. Push a sliver of garlic and a small sprig of rosemary into each. Rub with olive oil, salt and pepper.
- Sit it on a trivet of sliced onions and carrots in a roasting tin with a glass of water or wine.
- Roast for 20 minutes to brown, then turn the oven down to 180°C (160°C fan, gas 4) and roast for the time per kg above.
- Probe. Start checking the core temperature 15 minutes before the end, in the thickest part, away from the bone.
- Rest. Lift the lamb onto a warm board, cover loosely with foil and rest for 20–30 minutes. This is when the core finishes cooking and the juices settle. Make the gravy with the tin juices in the meantime.
Slow-roast leg of lamb
If you prefer lamb that falls off the bone, slow roasting is foolproof. Heat the oven to 160°C (140°C fan, gas 3). Put the seasoned leg in a deep tin on onions and garlic with 300ml of stock or wine, cover tightly with foil and roast for 4–5 hours for a 2–2.5kg leg, until the meat pulls away easily. Uncover for the last 30 minutes to brown. Serve it in chunks rather than slices.
How to carve a leg of lamb
Hold the shank end (the bone that sticks out) with a cloth. Cut slices from the meatiest side, at a slight angle, down to the bone. Then turn the leg and carve the other side. Finally, cut along the bone to release the slices. Carve across the grain for tender slices.
What to serve with roast lamb
Roast or boulangère potatoes, minted peas, spring greens or green beans, and gravy made with the tin juices and a splash of red wine. And of course, homemade mint sauce. For a quick finish, brush the leg with Middletons Garden Mint Glaze 110g (£1.99) for the last 15 minutes of roasting.
How big a leg of lamb do I need?
Allow about 350–400g of bone-in leg per person. Our Whole Carvery Leg of Lamb 2.2-2.7kg (£34.99) weighs 2.2–2.7kg, enough for six to eight people, with some leftovers. At 2.5kg, it takes about 1 hour 25 minutes for pink.
Leftover roast lamb
Cold roast lamb is excellent in sandwiches with mint sauce, in a shepherd's pie, or in a curry. Cool leftovers quickly and keep them covered in the fridge for up to two days, or freeze them for up to three months. Reheat until steaming hot throughout.
For other lamb cuts, read lamb cuts explained or what is hogget?, or browse our legs of lamb and the full lamb range.
Shop the cuts in this guide
How we pack your order
Your order is packed at our butchery at St Stephen, near St Austell, in a double-walled box with a sealed thermal liner and gel ice packs, then delivered by DPD next-day on the day you choose. Free delivery over £85.
Extra strong boxWhite double-walled corrugated cardboard
Thermal linerAir-infused, padded and sealed
Gel ice packsRecyclable film, non-toxic food-grade gel
DPD deliveryOn the day you choose
Leg of lamb cooking time FAQs
How long does a 1kg leg of lamb take to cook?
About 45 minutes for pink: 20 minutes at 220°C (200°C fan), then 25 minutes at 180°C (160°C fan). Allow about 50 minutes for medium. Rest it for 15–20 minutes.
How long do you cook a 2kg leg of lamb?
For pink, 20 minutes at 220°C (200°C fan) and then 50 minutes at 180°C (160°C fan), about 1 hour 10 minutes in total. For medium, about 1 hour 20 minutes.
What temperature should leg of lamb be inside?
As a cook's guide, take it out at 55–57°C for pink, 60–62°C for medium and 68–70°C for well done. It rises a few degrees as it rests.
Should you cover a leg of lamb when roasting?
Not for a traditional roast: leave it uncovered so it browns. Cover it tightly only for a slow roast.
How long should leg of lamb rest?
Rest it for 20–30 minutes, loosely covered with foil. A bigger leg benefits from the full 30 minutes.
