Roasting Beef Time Calculator

This roasting beef time calculator helps you exactly how long to cook your beef joint based on its weight and your preferred level of doneness.

When you’re cooking a beef roast, timing is everything. Cook it too long and you’ll end up with tough, chewy meat. Take it out too early and you risk serving raw beef to your guests. The calculator solves this problem by using proven cooking formulas that butchers and chefs have relied on for years.

Example: Let’s say you have a 1.5 kg beef topside joint and you want it cooked medium rare. You simply enter the weight, select medium rare as your doneness level, and choose your oven temperature (180°C). The calculator instantly tells you that you need 80 minutes of cooking time, and your target internal temperature should be 55-57°C. No more flipping through cookbooks or hoping for the best!

Roasting Beef Time Calculator

How Long Do I Roast Beef For Per Kg?

The cooking time per kilogram varies depending on how well-done you want your beef. There’s no single answer because different doneness levels require different internal temperatures, which means different cooking durations.

General Guidelines Per Kilogram (at 180°C):

• Rare: 30-35 minutes per kg
• Medium Rare: 40-45 minutes per kg
• Medium: 50-55 minutes per kg
• Well Done: 60-65 minutes per kg

Example Calculation:

You’ve bought a 2 kg beef rib roast and want it medium. Using the guideline of 50-55 minutes per kg:

• Take the middle value: 52 minutes per kg
• Multiply: 2 kg × 52 minutes = 104 minutes
• Add base time: 104 + 25 minutes = 129 minutes total
• That’s approximately 2 hours and 9 minutes

Keep in mind that several factors affect cooking time. If your beef is straight from the fridge, add 10-15 minutes. If it’s bone-in, it might cook slightly faster because bones conduct heat. The shape matters too – a long, thin roast cooks quicker than a thick, compact one.

Always use a meat thermometer to check the internal temperature. The times above are excellent guidelines, but every oven is different, and checking the actual temperature is the only way to guarantee perfect results.

Roast Beef Cooking Time Chart

Weight (kg)	Rare	Medium Rare	Medium	Well Done
0.5 kg	30 min	40 min	50 min	60 min
1.0 kg	45 min	60 min	75 min	90 min
1.5 kg	60 min	80 min	100 min	120 min
2.0 kg	75 min	100 min	125 min	150 min
2.5 kg	90 min	120 min	150 min	180 min
3.0 kg	105 min	140 min	175 min	210 min

Internal Temperature Guide:

• Rare: 50-52°C
• Medium Rare: 55-57°C
• Medium: 60-65°C
• Well Done: 70-75°C

All times based on 180°C oven temperature

Roasting Beef Time Example Calculations

Example 1: Small Family Roast

Details:

• Weight: 1.2 kg
• Doneness: Medium
• Temperature: 180°C

Calculation:

• 1.2 kg ÷ 0.5 = 2.4 units
• 2.4 × 25 min = 60 min
• 60 + 25 = 85 minutes
• Target: 60-65°C

Example 2: Large Dinner Party

Details:

• Weight: 3.5 kg
• Doneness: Medium Rare
• Temperature: 200°C

Calculation:

• 3.5 kg ÷ 0.5 = 7 units
• 7 × 20 min = 140 min
• 140 + 20 = 160 min
• High temp adjustment: 160 × 0.9 = 144 minutes
• Target: 55-57°C

Example 3: Quick Weeknight Roast

Details:

• Weight: 0.8 kg
• Doneness: Rare
• Temperature: 180°C

Calculation:

• 0.8 kg ÷ 0.5 = 1.6 units
• 1.6 × 15 min = 24 min
• 24 + 15 = 39 minutes
• Target: 50-52°C

Sources

1. BBC Good Food – How to Cook Perfect Roast Beef https://www.bbcgoodfood.com/howto/guide/how-cook-perfect-roast-beef
2. USDA – Safe Minimum Cooking Temperatures https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/safe-temperature-chart
3. Jamie Oliver – Roast Beef Guide https://www.jamieoliver.com/features/how-to-cook-roast-beef/