Beef Joint Calculator

For beef at 160°C fan (180°C conventional / gas mark 4): Rare is 20 minutes per 500g plus 20 minutes. Medium is 25 minutes per 500g plus 25 minutes. Well done is 30 minutes per 500g plus 30 minutes. So a 1.5kg joint at medium takes about (1500/500 x 25) + 25 = 100 minutes. These times follow the Waitrose roast-beef guide. Always verify with a meat thermometer for the most accurate results — for whole beef joints the surface should be fully seared, and reformed or minced beef must reach 75°C.

The target internal temperatures for a whole beef joint (measured with a probe thermometer in the thickest part, away from bone) are: Rare 52°C, Medium-rare 56°C, Medium 60°C, Medium-well 65°C, and Well done 71°C. Rare and medium are safe for an intact muscle joint because bacteria sit only on the surface, which is fully cooked when seared — but minced or reformed beef must always reach 75°C. Remember the temperature will continue to rise by 3-5°C during resting (carry-over cooking), so remove the joint about 3-5°C below your target.

The best cuts for roasting are topside, silverside, sirloin, rib of beef, and rump. Rib of beef (bone-in) is considered the finest roasting joint with excellent flavour and marbling. Topside and silverside are leaner and more affordable but can dry out if overcooked — medium-rare to medium is ideal for these cuts. Sirloin and rump have good fat content for a flavourful roast.

Searing is optional but recommended for the best flavour, and for whole joints it also helps ensure the surface bacteria are killed. Heat a heavy pan to smoking hot and sear the joint on all sides for 1-2 minutes each until well browned. This creates a Maillard reaction crust that adds deep flavour. Alternatively, start the oven at 220°C (200°C fan) for the first 20 minutes, then reduce to 180°C conventional / 160°C fan for the remaining time given by this calculator. Both methods achieve a similar result.

Allow approximately 300g of raw bone-in beef per person, or 200-250g for boneless joints. A 1.5kg boneless joint serves about 5-6 people. For a bone-in rib of beef, allow more weight per person as the bone adds weight without adding meat. If you want leftovers for sandwiches, add an extra 500g to your total.