Chicken Roasting Calculator

The standard UK formula is 20 minutes per 500g plus an additional 20 minutes at 180°C fan (200°C conventional / Gas Mark 6). So a 1.5kg chicken takes about 80 minutes, and a 2kg chicken about 100 minutes. Always verify with a meat thermometer — the juices should run clear and the thickest part of the thigh should read at least 75°C, the Food Standards Agency minimum for poultry.

Roast at 180°C fan (200°C conventional / Gas Mark 6) — this is the temperature the standard 20 minutes per 500g plus 20 minutes formula is calibrated to. Some recipes start at a higher temperature (220°C fan) for 15-20 minutes to crisp the skin, then reduce to 180°C fan for the remainder. This high-heat start produces crispier skin but needs more attention to stop the breast drying out. Whichever method you use, the thickest part of the thigh must reach at least 75°C to be safe.

Pat the chicken completely dry with kitchen paper before roasting. Rub the skin with olive oil or softened butter and season generously with salt. Do not cover with foil — exposed skin crisps better. For extra crispy skin, leave the chicken uncovered in the fridge overnight before roasting, which dries the skin. Roasting on a rack (not sitting in juices) also helps.

Rest a whole chicken for 10-20 minutes after removing from the oven, depending on size. A 1.5kg bird needs about 15 minutes. Tent loosely with foil and place on a warm plate. Do not wrap tightly or the crispy skin will go soggy from the trapped steam. Resting allows the juices to redistribute, making the meat more tender and easier to carve.

A standard 1.5kg chicken serves 4 people comfortably. A larger 2kg chicken serves 5-6. As a guide, allow about 400g of raw bone-in chicken per person. If you are serving with generous side dishes, you can stretch this further. For a meal with leftovers, go up a size.