How Long to Cook an 18-Pound Turkey

Everything you need to know about how long it takes to oven-cook an 18-pound turkey is shared. You do not need to be a professional chef to prep, cook, & serve up a juicy on the inside & crispy skin turkey. It will be moist, tender, & ready on time with this easy turkey roasting recipe.

All the best tips and tricks on how to cook an 18-pound turkey in the oven. Keep it moist, juicy, and flavorful while cooking it at either 325° or 350°. No guesswork - easiest recipe ever. You just have to follow the simple steps & use a good meat thermometer. The tastiest holiday or Thanksgiving turkey is just a few hours away.

This recipe for a seasoned turkey with lots of flavors couldn't be easier. With a little bit of planning and prep, later just let the oven do all the work.

You may want to smoke, deep-fry, or BBQ your turkey and that is great, but the cooking temperature and times will NOT be the same. What I outline below works for cooking your turkey in the oven. If you are roasting a turkey and it weighs 18 pounds (stuffing not included in the weight), be rest assured this recipe is what you need.

Jump to:

• Defrosting a Turkey
• Best Dry Brine for Turkey
• How to Prep a Turkey for Roasting
• Time & Temperature for 18-Pound Turkey
• Best Instant-Read Thermometer
• 18-Pound Unstuffed Turkey
• 18-Pound Turkey with Stuffing
• 18-Pound Turkey in a Roasting Bag
• Other Weights
• 18-Pound Turkey Feeds How Many People?
• Best Way to Store Leftover Turkey
• Recipes for Leftover Holiday Turkey
• TURKEY FAQS
• How Long to Cook an 18-Pound Turkey

Defrosting a Turkey

Be sure your 18-pound turkey is defrosted by the morning of the day you plan to cook it. For instance, if you want to bake it on Thanksgiving, I suggest getting it into the refrigerator the Friday before. This is because I always start a salt dry brine on Sunday and the turkey should not be solid frozen.

When thawing the turkey in a refrigerator, it takes 4-5 days to have a fully defrosted turkey that weighs 18 pounds. If you want to brine it, add 2-3 more days to your calendar. This will help you have a turkey that is ready.

Best Dry Brine for Turkey

I always suggest you start defrosting early so you can use a salt brine for your holiday bird. Brining the turkey will help keep it moist, juicy, & succulent. Try my easy process for the best dry brine recipe. 

If you are making your turkey for Thanksgiving day, which in America falls on a Thursday every year, you will need to start the dry brine on Sunday. Make sure your turkey has already started to defrost. It does not need to be completely defrosted but around ½-way through is fine. The skin and outer meat layers will be ready to absorb the salt and that is perfect.

How to Prep a Turkey for Roasting

Once your turkey has thawed, prep it for the oven. Get out a large roasting pan and rack. The disposable aluminum ones are fine too. If you are wondering how big a roasting pan you need for a turkey that is 18 pounds, it is a pretty big one. Ideally use a 14-inch pan and a rack that fits in it.

The last step before roasting a turkey is to add aromatics, spices, & herbs. Use whatever recipe you like, but below I have outlined how I season mine up. Simply remove the parts in the cavity of the bird, and add some aromatics like citrus, garlic, & herbs. Then rub on some softened butter and a homemade seasoning blend.

Time & Temperature for 18-Pound Turkey

You can cook a turkey at either 325° or 350° in the oven. Below is the information on how long to cook a turkey depending on the temperature you use. Whether your turkey is unstuffed or full of stuffing, here are how many hours it will take to roast in the oven. Plan ahead so it is ready on time for your Thanksgiving, Christmas, Easter, or other holiday meal.

I recommend cooking your turkey both covered and uncovered. I like to loosely tent foil over the turkey for the first half. Once it is halfway done, I remove the foil and let the skin begin browning so it is crispy and amazing. If left uncovered I find the skin gets too well done and the turkey may dry out.

Best Instant-Read Thermometer

Always use an accurate meat thermometer to check internal temperatures when cooking a turkey. I like to use an instant-read thermometer. I prefer this over leaving one in the turkey the entire time it cooks.

A good quality thermometer is the best way to check that your turkey is ready. With an instant-read thermometer, you can check several places on your turkey in a few seconds. It is best to check your turkey at the breast, thigh, & stuffing if your bird is stuffed. These recommendations for checking doneness are even shared by Butterball.

ALL TIMES SHARED HERE ARE ESTIMATES - EVERY TURKEY, OVEN TEMPERATURE, ROASTING PAN, ELEVATION, AND MORE CAN ALTER THE COOKING TIMES.

18-Pound Unstuffed Turkey

Once your 18-pound unstuffed holiday bird is in the pan and ready to go into the oven, make sure you set a timer to be sure you check it on time. If you are cooking the turkey at 325°, it will take 4-4 ½ hours to cook. At 350°, it will take 3 ½-4 hours. Place your turkey covered in foil in the oven and set a timer for 2 hours (halfway mark).

Once the halfway point is done, remove the foil so the turkey can cook uncovered for the final cooking time. I suggest using an instant-read thermometer and starting checking the thickest part of the thigh around the 3-hour mark. You want the turkey to reach an internal temperature of 175°.

Remember that at 325° it will take 30 minutes longer for the turkey to cook than if you cooked it at 350°. This is for a turkey without stuffing.

• 350° an 18-lb turkey takes 3 ½ -4 hours to cook in the oven
• 325° an 18-lb turkey takes 4-4 ½ hours to cook in the oven

18-Pound Turkey with Stuffing

If your 18-pound turkey is stuffed, in the pan, and ready for the preheated oven, time to set your timer. A stuffed turkey takes longer to cook than one that has no stuffing. If you are cooking the turkey at 325°, it will take 4 ½ - 5 hours to cook. At 350°, it will take 4 - 4 ½ hours.

Place the stuffed turkey covered in foil in the oven and set a timer for 2 hours. Remove the foil and reset the timer for 2 more hours. Use an instant-read thermometer and start checking the thickest part of the thigh around the 4-hour total cooking time mark. You want the turkey to reach an internal temperature of 175°.

Remember that at 325° it will take 30 minutes longer for the turkey to cook than if you cooked it at 350°. This is for a turkey with stuffing.

• 350° an 18-lb turkey takes 4 - 4 ½ hours to cook in an oven
• 325° a 18-lb turkey takes 4 ½ - 5 hours to cook in an oven

18-Pound Turkey in a Roasting Bag

If you like to cook your turkey in a bag, such as Reynold's bag, here is how long it will take for an 18-lb turkey. Cooking a turkey in an oven bag like Reynold's brand does speed up the cooking time. Since a turkey cooked in one of them cooks faster, I do not recommend stuffing a turkey when you cook in a bag. It can result in uneven cooking and the stuffing may be underdone and soggy.

When cooking an 18-pound unstuffed turkey in an oven bag at 350°, it takes around 3 - 3 ½ hours. I suggest starting to check the internal temperature of the turkey at the 3-hour mark. If the thickest part of the thigh is 175°, it is done.

Other Weights

If you have a really big party, family, or gathering where you are feeding a crowd, you may have more than one turkey. If you have different sizes and weights, they may cook at different times.

Try and buy them close in size if you can. For instance, turkeys just a few pounds less will cook for a similar amount of hours as one that is 18 pounds. The recipe for cooking a 15-17 pound turkey is done near the time an 18-pound turkey will be as well.

Here are some other guides for turkey cooking by weight.

• Cooking Times & Temperatures for a 12-Pound Turkey
• Cooking Times & Temperatures for a 20-Pound Turkey
• Cooking Times & Temperatures for a 25-Pound Turkey

18-Pound Turkey Feeds How Many People?

When estimating how many pounds of turkey per person, it is best to take into account those you are inviting. A combination of children, teens, and adults will feed more than a party with all adults that are big eaters.

On average, it is best to estimate 1 - 1 ½ pounds per person. For a family of adults and children that are average eaters, an 18-pound turkey will feed 15 people. If it is all adults or big eaters, estimate it to feed 12 people.

With several hearty sides and part of a large Thanksgiving meal, an 18-pound turkey will feed roughly 16-18. After all, everyone wants to save room for dessert, right!?!

Best Way to Store Leftover Turkey

Leftover turkey stores well in the refrigerator. Place slices or pieces in an air-tight container. Store turkey in the refrigerator for up to 5 days. No need to remove the bones before storing but you can if you wish. Save those bones to make a healthy bone broth using bones in an Instant Pot or electric pressure cooker!

Turkey also freezes well and is easy to do. Place the leftover Thanksgiving turkey in an air-tight container. Store it with or without the bones. I prefer removing the meat from the bones before freezing. It saves freezer space but it also helps it defrost faster and more evenly later.

To defrost the leftover frozen turkey, place your container in the refrigerator. Let it thaw for 1-3 days, depending on the amount. Enjoy cold in a sandwich or salad. I love it in a bowl of comforting Pot Pie Soup.

Or reheat leftover turkey in a toaster oven or oven at 350° for 5-20 minutes depending on how much you are warming up (and if it thin slices or the whole turkey leg - haha!)

Recipes for Leftover Holiday Turkey

Besides building a tasty sandwich, here are more recipes and ideas for using up leftover turkey slices & other pieces. Trade out the protein or add the turkey to the existing recipes below and continue getting your turkey fix for days after Thanksgiving or Christmas. (The kale salad or the curry are my favorite ways to use up the turkey!)

• Pot Pie Soup
• Butternut Squash, Apple, and Kale Salad with Honey Dijon Vinaigrette
• Zucchini, Chickpea, and Potato Curry
• Toaster Oven Grilled Cheese Sandwich

TURKEY FAQS

Is it better to cook a turkey at 325° or 350°?

You can cook a turkey at either temperature, 325° or 350°. I personally cook at 325° for a low and slow oven-roasted turkey that is juicy every year. I do not recommend cooking it at a higher temperature to speed things up. It simply dries out the skin & sections of the outer meat too fast while the internal meat like the thigh could still be unsafe & undercooked.

How to keep a turkey moist when cooking in the oven?

Here are my top tips to keep the turkey moist and juicy. Begin with a dry brine for several days before cooking. Before cooking the turkey, coat the skin with softened butter. Also, cover the turkey in foil for the first ½ of cooking to keep the moisture from escaping.

Finally, make sure to let the turkey rest for at least a half hour before carving it. This is true for most meats and poultry - the rest is best! Even the breast will be moist after oven cooking. All of these ideas are the best way to keep a turkey from drying out.

Do you need to pour water into the bottom of a turkey roasting pan?

If you do all the above things I described, your turkey will be moist. Adding water to the pan is not necessary. You don't want to "steam" your bird, you want to roast it slowly and evenly. The water at the bottom will add steam to the oven plus it will be like a hot bath that the turkey is sitting in.

Even if just a few inches, part of the bird will almost boil if water touches or has submerged parts. And that section will cook faster than the rest of the turkey. Also, as the turkey juices and melted butter collect at the bottom of the pan, why would you want them watered down? They taste so much better when concentrated with full flavor.

What internal temperature should a cooked turkey be?

There are 3 places you may check your turkey for doneness and each has a different reading. Using an instant-read thermometer, you want the turkey breast to read 165° and the thickest part of a thigh to read 175°. If you have stuffing, check that as well for a temperature of 165° also.

IMPORTANT - turkey will continue to "cook" as it rests. It will likely go up another 5° during that time and that IS OK! It is best to let the turkey rest for a minimum of 30 minutes before cutting into it & it will be perfectly moist and done. Tent it with foil & wait until later before you start carving it. If you carve it too soon, the juices will run out and dry out the meat.

If your bird has stuffing, the stuffing needs to be safe to eat as well. You do not want undercooked stuffing that may be harmful to consume. Make sure the stuffing is 165° so that any turkey juices that have dripped into it are also safe.