What does this tool do?
Roasting time scales with weight, but the meat, target doneness and oven temperature all shift the minutes per kilogram. This calculator gives a starting time and the internal temperature to check, so you can rely on a thermometer rather than the clock alone.
The Formula
Oven time = weight (kg) × minutes per kg × oven factor + base timeFrequently Asked Questions
Should I cover the roast?
Covering traps steam and slows browning. For a crisp surface, roast uncovered and tent loosely with foil during resting; for a braise-like result, cover after the first 30 minutes.
Why is my roast taking longer than calculated?
Bone-in and irregular roasts conduct heat slowly, a cold start adds time, and opening the oven drops the temperature. Trust the thermometer and add time in 10-minute increments if needed.