What is the formula for roasting beef?

For beef at 180°C fan: 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. Always verify with a meat thermometer for the most accurate results.

What are the internal temperatures for beef doneness?

The target internal temperatures for beef (measured with a probe thermometer in the thickest part, away from bone) are: Rare 52°C, Medium-rare 57°C, Medium 60°C, and Well done 70°C. Remember that the temperature will continue to rise by 3-5°C during resting (carry-over cooking), so remove the joint about 3°C below your target.

Which beef cuts are best for roasting?

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.

Should I sear beef before roasting?

Searing is optional but recommended for the best flavour. 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 for the first 20 minutes, then reduce to 180°C. Both methods achieve a similar result.

How many people does a beef joint serve?

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.

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Beef Joint Calculator

Calculate cooking time for beef joints based on weight and preferred doneness.

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How We Calculate This

This calculator uses the standard UK beef roasting formula at 180°C fan. The time per 500g increases with doneness: 20 minutes for rare, 25 for medium, and 30 for well done, each with a matching additional base time. Medium-rare is interpolated between rare and medium.

Resting time is calculated at 1 minute per 100g, with a minimum of 15 minutes and maximum of 30 minutes. Internal temperatures account for approximately 3-5°C of carry-over cooking during rest.

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Last updated: February 2026

All calculations are based on standard ratios and conversions. Results may vary with specific ingredients, equipment, and conditions.