Can You Microwave Cardboard? Safe Or Not? [Updated 2023]

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Sometimes you are going to take dinner and there’s leftover takeout in the fridge. The question is that can you microwave cardboard because you need to reheat it. Or is it safe to reheat food with cardboard? We say yes but on the other hand, we say no. so the answer is both yes and no.

Basically, you can microwave cardboard but microwave under some conditions otherwise microwaving might be going dangerous.  In this article, we will explain everything in detail, you just need to read this helpful guideline.

Is it safe to microwave cardboard?

Well, it is safe to microwave cardboard but when it is pure cardboard or a container that is made of pure cardboard. In this way, you can microwave cardboard without causing any damage to the food, container, or oven itself. Always keep in mind that some types of cardboard are not safe to be microwaved.

Especially, Cardboard containers that have wax, plastic, glue, ink, or metal as a coating on the outside or inside. So, when you are planning to microwave your food with cardboard then you need to read the label on the cardboard whether it is microwaveable or not.

Basically, some Cardboard containers have chemicals that might be quite hazardous when you heat the cardboard in a microwave. In this way, the compounds can leach into your meal and make it poisonous and unhealthy. So, in order to use the cardboard safely inside a microwave oven, then you need to read the label first.

Can you microwave cardboard

So, after checking out the label, if it is microwaveable and now you’re using this microwave-safe cardboard then you need to be careful about the time period. You have to microwave it for short time.

Always keep it between 1 to 2 minutes, and make sure to check after 30 seconds to decrease the risk of overheating the cardboard. One more thing is that the power setting should be low. But if you need to heat your food up for longer, then you should transfer the food to another microwave-safe container.

Because cardboard is flammable, infect cardboard is a quick conductor of fire, it can easily catch fire. Infect, the cardboard contains wood fiber such as cellulose same as used in the paper. It has a 9 to 12% of moistening level.

So, when you microwave the cardboard, the moistening level will start to decrease. When the level comes to 1% then the fibers become dry, and they will easily catch fire due to overheating, it can also catch fire especially at temperatures of over 400°F or for long periods of time. Because the moisture level in the cardboard is too low that making it more likely to catch on fire.

However, it is not a major concern under ordinary circumstances. Especially, when the cardboard boxes are made of pure wood fiber that’s why it is safe to be microwaved.  However, cardboard boxes contain small metal elements in order to keep the pieces together. So if you microwave the cardboard with this thin plastic coating then heating cardboard in the microwave can be dangerous.

Types of the Cardboard You Can’t Use in the Microwave

So these are some types of cardboard that you can’t microwave because the common cardboard containers you should not microwave due to some basic reasons. Take a look at these microwaveable types of cardboard:

  1. Cardboard that contains any kind of glue or another adhesive. While heating, it can release chemicals into your food. That never be good for your health.
  2. Cardboard that includes ink printed on it, it will also release chemicals into your food when you hear it in your microwave and this food must be dangerous for you.
  3. Cardboard that has a lining is also not microwaveable. Because Wax and plastic linings can easily release chemicals and fumes into your food that is also unhealthy for you…

Tips to use Microwave Cardboard

Microwaving cardboard is safe does not mean there can be any risk. There might occur some risks by overheating.

Can you microwave cardboard

So, here are some helpful tips for Can you microwave cardboard:

  • First of all, Make sure to check the label before using cardboard in the microwave oven.
  • Must check if there is any waxed or coated plastic on the cardboard because these two elements can easily be hazardous when they heat up in the microwave.
  • You have to set a short time on your Microwave when you heat the cardboard. The short durations mean 60 to 120 seconds with low temperatures.
  • You should always remove paper, plastic, or metal pieces before you microwave the cardboard.
  • If you need to heat food for a long time then it is better to transfer the food or beverages to a microwave-safe bowl.


In the end, we will say cardboard is generally safe to be used in the microwave but we will recommend you read the manufacturer’s instructions before microwaving any kind of material. Same as you should do while microwaving cardboard. Sometimes reheating instructions are mentioned on the cardboard package whether you can microwave this cardboard or not.

Always keep the temperature low and don’t heat the cardboard for a long time otherwise it can be dangerous. So your personal safety must be the first priority. So that is all, you need to know about “Can you microwave cardboard”. We hope this article will help you a lot!

Sania Imtiaz

Hi, My name is Sania Imtiaz and I’m from Pakistan. I’m a housewife. And I Love cooking. And I’m a believer in making life peacefully with FOOD. I’m doing cocking from the last 10 years and I’m sharing all my knowledge related to cooking on I’m sharing all my experience on this site related to cooking products.

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