Preparing a turkey for a family meal requires planning. Perhaps the most important part of this is knowing when you need to get your bird in the oven. Once you've got it cooking, you can get back to work on other things and leave it until it's done. Exactly how long your turkey will take to cook depends on how much it weighs.

Weight the turkey before you put it in the oven. Don't forget to weigh it stuffed if you're going to stuff it; the added weight isn't much, but it can make a difference. A stuffed bird will typically take a little longer to cook than an unstuffed one.

Heat your oven to 325 degrees Fahrenheit if you want to cook at a steady temperature. This method involves the least work but can take a little longer. Alternatively, if you're in a hurry, you can start by heating the oven to 400 degrees Fahrenheit and then reduce the heat.

If you're cooking your turkey at a steady 325F, the length of time it will take to cook varies by weight. A turkey of up to 12 pounds should cook in about 3 hours. If it's stuffed, it could take as long as 3 1/2 hours, while an unstuffed turkey might be done in as little as 2 3/4 hours. A turkey of up to 14 pounds should take around 3 1/2 to 3 3/4 hours. Again, an unstuffed turkey might take a little less time, while a stuffed bird could take longer. A turkey between 14 and 18 pounds will take around 4 hours, while a turkey between 18 and 20 pounds should take about 4 1/2 hours. A really massive turkey of up to 24 pounds could take 5 hours or more.

If you plan to alter the temperature during cooking, your turkey will be done a little more quickly. Cook the bird at 400F for the first 15 minutes, and then reduce the oven temperature to 350F. At this temperature, a 6-pound turkey will be done in about 1 3/4 hours. Add 15 minutes for every extra 2 pounds to calculate an approximate cooking time.

These cooking times are approximate; the perfect cooking time for your turkey will vary slightly. As you get close to the recommended time, use a meat thermometer to check the turkey's temperature. Test the temperature at the thickest part of the thigh, but be careful not to touch the bone. Ideally, you want your turkey to reach around 160F.

Once you've removed the bird, cover it in foil and let it stand for at least 30 minutes. The turkey is still cooking, and for a short time its temperature will actually increase. The target temperature is 165F.