Whether you’re heating up a pizza or re-heating other types of leftovers, the question many come up as to whether or not you can you put cardboard in the oven? This article answers the question and offers other alternatives to putting cardboard in the oven.

pizza in a cardboard box.

Why Would I Want to Use Cardboard?

We all reach for a frozen pizza at one time or another. It is a fast meal at the end of a long day, and there really are some great options to fit many different lifestyles.

Many come on top of a cardboard circle and, if you read closely, the package will tell you not to put it in the oven.

There are also nice takeout options for pizza, and a lot of people simply put the entire pizza box in the fridge when they are done with their meal, and then decide to reheat the pizza in that box.

This seems very convenient, right?

Reasons Not to Put Cardboard in the Oven

While your pizza does come in a cardboard box, the package more than likely says not to put it in the oven.

It is of course a paper product, and you use parchment paper in the oven, don’t you?

But, even parchment paper has limits. Some of them say not to use in your oven about 425 degrees. Even at that point if you have it too close to the heating element it can darken and even catch fire.

Your cardboard pizza box could catch fire as well!

It’s best to put your leftover pizza on a cookie sheet, baking sheet, pizza pan, or pizza stone as opposed to a cardboard base or pizza box.

You don’t want to risk a kitchen fire by putting your pizza cardboard box in the oven.

You may think you won’t have it in there long, or not too high of a temperature, but we all have forgotten things in the oven for longer than we intend to! It could very easily catch fire and you might not realize it right away.

Many cardboard is coated in wax or other sealants and harmful chemicals. This way they won’t soak in too much condensation if your frozen foods thaw a little in transit. However, those chemicals could then melt or leach into the food you are heating on them.

Besides being unsafe to eat then, it can also add a cardboard taste into the food.

Safer Ways to Heat Leftovers

1. Microwave

If you use a microwave oven, it is a great option for things like soups where you will stir them a few times during heating. This helps them heat evenly.

If you want to reheat pizza in the oven, place pizza on a ceramic plate first. Then, heat the leftover pizza for 1-2 minutes until it’s hot.

The pizza may not be as crispy, but the microwave is the easiest way to reheat your leftovers.

leftover chinese takeout in white containers.

2. Air Fryer

The air fryer is an excellent choice for reheating leftovers, especially pizza. I personally think it’s the best way.

Set the air fryer to around 360°F for about 5-7 minutes to reheat pizza slices. Just place your leftover pizza directly inside the air fryer basket or bottom of the oven. You don’t need tin foil.

The air fryer can also be used to reheat other types of leftovers including lasagna, potatoes, vegetables, and more. The water molecules will reheat quickly and reheating leftovers is a good reason to get an air fryer.

See my list of the best air fryers under $100.

leftover cauliflower in air fryer.

3. Stovetop

The stove is always a great option for reheating leftovers.

An option for reheating pizza is to put your slices in a skillet to crisp the bottom, and a lid helps melt the cheese from the top while getting a crispy crust. Try to use a low temperature to prevent burning.

It won’t be crispy, but it won’t be as rubbery as if you used a microwave.

pans on the stove.

4. Toaster Oven

If you have the counter space, toaster ovens are exceptional. They don’t heat up the kitchen as much as a regular oven, and have lots of options to choose from.

You should be able to achieve the same texture as the first time you cooked the pizza! You will also have an easy way to heat up leftover waffles and pancakes.

Older ovens make need a higher temperature, but try to use an oven temperature of around 350 degrees F to get your cold pizza hot again.

Be sure to take the pizza out of the box and don’t use any cardboard in a toaster oven to reduce the risk of fire.

You can also cook a frozen pizza in the toaster oven, just follow the ingredients on the package and remove any cardboard containers or pizza boxes.

pizza in the toaster oven

5. Instant Pot

While I haven’t tried it myself, I have heard of people using the “pot in pot” method in their Instant Pot to heat leftovers.

Add water to the Instant Pot liner and set your food in a heat safe dish on the trivet, and steam for a few minutes.

This would work also well for meats and other foods where you want to retain moisture.

leftover soup in the instant pot


Can I put aluminum foil in the oven?

Yes, most aluminum foil is safe in the oven for high temperatures, up to around 500 degrees Fahrenheit.

Is any cardboard safe for the oven?

Not likely. The only cardboard that could be safe for the oven is a special type of cardboard that states directly that it can be placed in the oven. In most cases, you should not put a piece of cardboard in the oven which includes a toaster oven and an air fryer oven.


While the cardboard your pizza comes on seems very convenient for cooking and reheating, just remember that you don’t want those chemicals in and on your food. You’ll get a bitter taste plus you might create a fire risk.

Always follow directions on the packaging so you get the best texture and flavor on your meals. The cardboard circle is an easy way to get your pizza in and out of the oven, and to use as a cutting board.

Just don’t put cardboard boxes in the oven!

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About the Author: Carrie Forrest has a master’s degree in public health with a specialty in nutrition. She is a top wellness and food blogger with over 5 million annual visitors to her site. Carrie has an incredible story of recovery from chronic illness and is passionate about helping other women transform their health. Send Carrie a message through her contact form.