If you start roasting a 14-pound turkey at 375 degrees at 7 a.m. and need to feed 15 people – including three vegetarians, 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 pumpkin pie is cut into 11.75 equal wedges?

Or am I the only cook who suffers flashbacks to grade-school word problems every time I try to calculate the many 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 different-size turkeys feed to how many pounds of carrots and cans of cranberry sauce you'll want for making sure your crowd leaves the table stuffed.

And because we're talking Thanksgiving, 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 is fine; they have a higher meat-to-bone ratio. But if your goal is to have very ample leftovers, aim for 11/2 pounds per person, no matter how big the turkey is.

• For 8 people, buy a 12-pound turkey.

• For 10 people, buy a 15-pound turkey.

• For 12 people, buy an 18-pound turkey.

• For 14 people, buy a 20-pound turkey.

The big thaw

The safest way to thaw a frozen turkey is in the refrigerator. You'll need about 24 hours per 4 to 5 pounds of turkey. For speedier thawing, put the turkey in a sink of cold water. Change the water every 30 minutes, and plan for about 30 minutes per 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 your bird). Be certain the brine is completely cooled before adding the turkey.

Turkeys should be brined for at least 8 to 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.

Keep the bird refrigerated during brining. If the turkey is too big, an ice-filled cooler stored outside works, too.

The roast

Roasting temperatures vary widely by recipe. Some cooks go at a slow and steady 325 degrees. Others crank the heat to 400 or 425 for the first hour, then lower it 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 degrees for safe eating, though some people say thigh meat tastes better at 170 degrees.

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 per 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

• 15-pound turkey: 4 to 41/2 hours at 325

• 18-pound turkey: 41/2 to 5 hours at 325

• 20-pound turkey: 5 to 6 hours at 325

The baste

Basting the bird with its juices helps crisp the skin and flavor the meat. Do it every 30 minutes, but no more. Opening the oven door too frequently lets heat escape and can significantly slow the cooking.

The rest

The turkey never should go directly from the oven to the table. Like most meat, it needs to rest before serving for the juices to redistribute. Cover the turkey with foil and a few bath towels layered over that (to keep it warm), then let it rest for 20 to 30 minutes.

The sides

• Carrots: A 1-pound bag makes 4 to 5 servings.

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

• Gravy: Plan for 1/3 cup of gravy per person.

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

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

• Stuffing: A 14-ounce bag of stuffing makes about 11 servings.

The leftovers

For food-safety reasons, leftovers should be cleared from the table and refrigerated within two hours of being served. Once refrigerated, they should be consumed within three to four days. Leftovers can be frozen for three to four months. Though safe to consume after four months, they will start to develop off flavors.

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