If you start roasting a 14- pound turkey at 375 degrees at 7 a.m. and need to feed 15 people, including a vegetarian, a vegan and two gluten intolerants, by 1 p.m., how many pounds of cranberries do you need if the stuffing is baked outside the bird and the pie is cut into 11.75 equal wedges?

Am I the only cook who suffers flashbacks to grade school word problems every time I try to calculate the mathematical angles of assembling Thanksgiving dinner?

Fear not. I took one for the turkey team and did the math for you, sorting out all the numbers you need, from how many people a turkey feeds to how much carrots and cranberry sauce you’ll need to satisfy your crowd.

All serving estimates are generous to allow for plenty of seconds and leftovers.

How big?

For turkeys less than 16 pounds, estimate 1 pound per serving (this accounts for bone weight). For larger birds, a bit less; they have a higher meat-to-bone ratio. But if your goal is to have ample leftovers, aim for 11/2 pounds per person no matter how big the turkey.

For 8 people: Buy a 12-pound turkey

For 10 people: 15-pounder

For 12 people: 18-pounder

For 14 people: 20-pounder

The big thaw

The safest way to thaw a fro- zen turkey is in the fridge. You’ll need about 24 hours per 4-5 pounds of bird. For speed-ier thawing, put the turkey in a sink of cold water. Change water every 30 minutes; plan for about 30 minutes a pound.

The brine

A good brine uses kosher salt and sugar in a 1-to-1 ratio, and usually no more than 1 cup of each. Feel free to add any other seasonings. Brines typically are made by heating the salt, sugar and seasonings with a bit of water until dissolved. This mixture then is diluted with additional cold water (volume will vary depending on the size of bird). Be sure brine is completely cool before adding the turkey.

Turkeys should be brined for at least 8-10 hours, but can go as long as 72 hours. A good rule of thumb is, the longer the brine, the weaker the brine. So for a 10-hour soak, use 1 cup each of salt and sugar. For a longer one, consider backing down to 3/4 cup each.

Always keep the bird refrigerated during brining.

The roast

Roasting temperatures vary widely by recipe. Some go at a slow and steady 325 F. Others crank the heat to 400 or 425 for the first hour, then drop it down for the rest of the time.

However you roast, use an instant thermometer inserted at the innermost part of the thigh (without touching bone) to determine when your turkey is done. The meat needs to hit 165 F for safe eating, though some people say thigh meat tastes better at 170.

If the outside of the bird gets too dark before the center reaches the proper temperature, cover it with foil.

The following roasting time estimates are based on a stuffed turkey cooked at 325 degrees. Reduce cooking time by 20 to 40 minutes for turkeys that are not stuffed (estimate total roasting times at 15 minutes/pound for unstuffed birds). And remember, a crowded oven cooks more slowly, so plan ahead if your bird needs to share the space.

12-pound turkey: 3 to 4 hours at 325 degrees

15-pound bird: 4-41/2 hours

18-pound bird: 41/2-5 hours

20-pound turkey: 5-6 hours

The baste

Basting the bird with its juices helps crisp the skin and flavor the meat. Do it every 30 minutes, no more. An open oven door can slow cooking.

The rest

The turkey never should go from oven to table. It needs to rest for the juices to redistribute. Cover turkey with foil and bath towels layered over that (to keep it warm), then let it rest 20-30 minutes.

The sides

Carrots: 1-pound bag makes 4 to 5 servings

Cranberry sauce: 12-ounce package of fresh cranberries makes about 21/4 cups of sauce; a 16-ounce can has 6 servings

Gravy: 1/3 cup per person

Green beans: 11/2 pounds of beans makes 6 to 8 servings

Mashed potatoes: 5-pound bag of potatoes makes 10 to 12 servings.

Stuffing: 14-ounce bag makes about 11 servings.

The leftovers

For food safety, leftovers should be refrigerated within two hours of being served, and they should be consumed within three to four days. Leftovers can be frozen for three to four months. Any longer than that and they may taste off.