Lamb Cooking Time Calculator

Lamb cooking time is calculated per kilogram, with the doneness level determining the minutes per kg. A leg of lamb is the classic Easter and Sunday roast cut in the UK. At 180°C (Gas Mark 4), a 2kg leg needs 50–60 minutes for medium (pink) doneness, plus 15 minutes resting. The starting sear at 220°C for 20 minutes develops the flavour and crust.

Unlike chicken, which must reach 75°C for food safety, lamb can be served pink. The UK Food Standards Agency confirms that whole lamb joints can be served with a pink centre, as any surface bacteria is killed during cooking. An internal temperature of 60°C for pink and 65°C for medium is both safe and delicious for leg and rack of lamb.

Shoulder of lamb is a very different proposition to leg. While leg is a lean, tender muscle suited to high-heat roasting, shoulder has much more connective tissue and fat. It is best cooked low and slow — 160°C for 4–5 hours — where the collagen breaks down into gelatin, producing falling-apart, deeply flavoured meat. For pulled lamb, cook to an internal temperature of 85–90°C.

The Easter and spring lamb season means the timing tool gets heavy use from March to April. Key things to remember: bring lamb to room temperature before cooking, rest generously after cooking, and use a thermometer rather than relying on cooking time alone, as joint shapes vary considerably.