My mom is asking. Not sure if she's brining the turkey, but probably. Also, she probably knows the answer but is just testing me.
2 Answers
Per Food Network, plan on 20 minutes per pound at 350F (177C), up to 30 minutes more for a stuffed turkey. Whatever you do, don't count on that silly pop-up thermometer thing, use a real thermometer. The thickest part of the thigh and the stuffing should register 165F (74C). Don't forget to let it rest for at least 30 minutes.
For what it's worth, stuffing a turkey is criminal. Check out what Serious Eats has to say.
The answer is going to vary greatly, depending on (1) size of bird, (2) oven roasting temperature, and (3) desired final temperature.
The USDA provides helpful tables here for both stuffed and unstuffed turkeys of various sizes, roasted at what the USDA considers the minimum safe roasting temperature for turkeys (325F), arriving at what the USDA considered the minimum safe final temperature of 165F. (Other chefs or safety organizations may recommend different temperatures here.) The "X minutes per pound" rules generally don't work very well, because cooking time does not increase linearly with size of bird.
As Jolenealaska said, use a thermometer. Don't rely on things like "X minutes per pound" rules or on color of the flesh or on the color of the juices -- all of these can be inaccurate, and they will not tell you whether your stuffing has reached a safe temperature. Use a thermometer to check both the thickest part of the thigh and the center of the stuffing to be sure the turkey has reached your desired temperature. (The USDA would also tell you to check the bottom of the wing and the thickest part of the breast. These are particularly important for large turkeys, if your bird may not have been completely defrosted, or if the stuffing causes uneven cooking.)