How long to roast a whole chicken (by weight, with a worked example)

How to · Updated 2026-11-10

Allow about 40 to 50 minutes per kg at 190 °C, then trust a thermometer: the thickest part must reach 74 °C. A 1.8 kg bird worked through.

A whole chicken takes roughly 40 to 50 minutes for every kilogram in an oven at 190 °C (375 °F), so a typical 1.5 to 2 kg bird needs about 1 to 1¾ hours. The time only tells you when to start checking: the bird is ready when a thermometer in the thickest part reads 74 °C (165 °F). The roast time calculator turns the weight on the label into a time range, an oven setting and a target temperature.

What you need

• The raw weight of the bird. It is on the label, in kg or lb; or weigh it without the packaging.
• An oven that holds a steady heat. Know whether yours is a conventional oven or a fan (convection) oven, because a fan cooks faster.
• A meat thermometer. A cheap instant-read probe is fine; it is the only real test of doneness.
• About 15 minutes at the end for the bird to rest before you carve it.

Step by step

The sum behind every roasting chart is simple:

Time = weight × minutes per kg

With the usual rule of 40 to 50 minutes per kg, you get a short time and a long time. Begin checking at the short one.

1. Open roast time and choose Chicken (whole) from the Meat list.
2. Type the weight and pick kg or lb. If you change the unit after typing, the page converts the number for you, and the minutes-per-unit boxes follow.
3. Read the large time range at the top of the results. The rows underneath give the oven setting (190 °C, or about 20 °C less in a fan oven), the temperature to aim for and how long to rest the bird.
4. If your recipe uses a different rule, edit the two Minutes per kg boxes (from and to). The range updates as you type.
5. Put the chicken in, set a timer for the low end of the range, and probe the thickest part of the thigh and the breast, keeping the tip away from the bone.
6. When it reads 74 °C, take it out, cover it loosely with foil and leave it for 10 to 15 minutes. The juices settle and the heat keeps spreading inward.

If your recipe is written in gas marks or Fahrenheit, the oven temperature converter gives the matching dial setting. Cooking two smaller birds for a crowd? The recipe scaler can resize the stuffing and sides to the number of guests.

A worked example

You bought a 1.8 kg chicken and have a conventional oven.

• In pounds, 1.8 × 2.20462 = 3.97 lb, which the page shows as 4 lb.
• Short time: 1.8 kg × 40 min/kg = 72 minutes.
• Long time: 1.8 kg × 50 min/kg = 90 minutes.

The tool rounds to the nearest 5 minutes, so it shows 1 h 10 min to 1 h 30 min. Heat the oven to 190 °C (375 °F, gas mark 5). In a fan oven, set about 170 °C instead.

Start probing at 1 h 10 min. Say the thigh reads 68 °C: put it back and check every 10 minutes. At about 1 h 25 min both thigh and breast read 74 °C or more, so it is done. Rest it for 10 to 15 minutes and carve. If you live in Canada, note that Health Canada lists 82 °C for a whole bird, so you would leave it in a little longer.

Check your answer

• Rough check in your head: an hour for the first 1.5 kg, plus about 10 minutes for each extra 250 g. For 1.8 kg that gives just over 1 hour 10 minutes, in line with the short end above.
• Look at the juices and the leg. When the bird is cooked, the leg moves easily in its joint and the juices from the thigh run clear rather than pink. These are hints only; the thermometer is the real test.
• If the time looks far off, check the unit. A 1.8 typed with lb selected gives roughly half the time you need for a 1.8 kg bird.

Questions people ask

Should I cover the chicken with foil while it roasts? You can, if the skin is browning too fast. Take the foil off for the last 20 minutes or so to crisp it. Covering changes the colour more than the time.

Does a stuffed chicken take longer? Yes, because the stuffing slows the heat reaching the middle. Many cooks bake the stuffing in a separate dish instead. If you do stuff the bird, the centre of the stuffing must reach 74 °C too.

Can I roast a chicken straight from frozen? It can be done, but it takes about half as long again and cooks unevenly. Thawing it fully in the fridge first gives a more even result and a time you can plan around.