Can You Microwave a Pizza Box? What You Need to Know Before Reheating Pizza

Generally, no you shouldn’t microwave pizza in its takeaway box unless the packaging is specifically labelled as microwave-safe.

It might seem harmless. You have leftover pizza, the box is already sitting in the fridge, and putting the whole thing into the microwave saves a plate and a few seconds of effort.

But pizza boxes are designed primarily for transporting and serving pizza, not necessarily for microwave heating.

The cardboard itself isn't the whole story. Depending on the box, there may also be printing inks, adhesives, grease-resistant treatments, coatings, labels or metal components. Heating food inside packaging that hasn't been designed and tested for microwave use can therefore introduce unnecessary risks.

For the safest option, take the pizza out of the box and place it on a microwave-safe plate.

Why shouldn't you microwave a pizza box?

A pizza box is usually made from corrugated paperboard, and plain cardboard does not automatically behave like metal in a microwave.

The problem is that a commercial pizza box is more than just cardboard.

Depending on how it has been manufactured, it may contain or be exposed to:

• Printing inks

• Adhesives

• Grease-resistant treatments

• Coatings or barrier layers

• Labels or stickers

• Metal staples, ties or other components

• Grease and food residue

This is why the safest approach is not to ask whether cardboard can go in a microwave, but whether that particular packaging has been tested and labelled for microwave use.

The research cited in support of this article raises issues related to the presence of certain substances in food contact paper and board such as PFAS, bisphenols, and mineral oil-related substances.

This does not imply that all pizza boxes will release hazardous chemicals when heated. What it implies is that there is no justification for a consumer to take a risk when it takes just a few seconds to move a pizza slice onto a microwaveable plate.

Can cardboard catch fire in a microwave?

Yes, cardboard can eventually overheat and burn.

A microwave doesn't heat cardboard in exactly the same way that an oven does. However, the food inside the box can create very hot areas, while grease can make parts of the packaging more vulnerable to scorching.

The research reviewed for this article notes that cardboard can ignite at temperatures of roughly 232°C (450°F) and that dry or greasy cardboard can become a fire concern if it overheats.

The risk is particularly concerning when:

• The box contains metal

• The cardboard is extremely dry

• There is a large amount of grease

• The microwave is operated for too long

• The box contains metallic printing or other conductive components

• The packaging is left unattended

What if you see sparks?

Stop the microwave immediately.

Sparks or arcing can occur when microwaves interact with metal components. Some pizza packaging can contain staples, metal ties or other metallic elements.

Whirlpool's guidance, cited in the research, specifically recommends removing food from cardboard containers and placing it on a microwave-safe plate because cardboard packaging can contain materials such as glues, waxes or metal fasteners.

If you notice sparking, smoke or charring, don't continue heating the pizza in the box.

What about the chemicals in pizza boxes?

This is where the question becomes more interesting.

The obvious concern with microwaving cardboard is fire. But food-contact packaging chemistry is another reason to avoid heating an ordinary takeaway box unless it has been designed for that purpose.

PFAS and grease-resistant pizza boxes

PFAS, short for per- and polyfluoroalkyl substances, are a large group of chemicals known for their resistance to grease, oil and water.

Historically, certain PFAS have been used in grease-resistant food packaging.

Research cited in the supplied material reports PFAS findings in pizza boxes, including samples from Domino's and independent pizza shops. The reported testing found total fluorine/PFAS-related measurements in some samples at approximately 55–70 μg/dm².

However, there's an important distinction:

Finding PFAS in some packaging does not mean that every pizza box contains hazardous levels of PFAS, nor does it prove that microwaving a particular box will cause harmful exposure.

The UK's Food Standards Agency has been monitoring PFAS in food and food-contact materials, and the research supplied for this article notes that initial UK testing found negligible levels in the pizza-box samples tested.

This is exactly why a responsible packaging article should avoid saying “microwaving a pizza box will poison you.” The evidence doesn't justify that statement.

A better conclusion is:

If a pizza box isn't specifically designed and labelled for microwave heating, there is no benefit in exposing your food to packaging materials that haven't been demonstrated to be suitable for that use.

What about BPA and BPS?

PFAS aren't the only packaging chemicals attracting attention.

A 2024 German consumer investigation cited in the research found bisphenols including BPA and BPS in many pizza boxes tested, with laboratory testing also examining migration into food. The supplied research reports particularly high migration results for BPS in some tests.

Bisphenols are particularly relevant because some are known for their endocrine activity.

However, once again, the findings shouldn't be turned into a blanket statement that all pizza boxes are unsafe.

The more useful takeaway for consumers is simpler:

Food packaging should be used for the purpose it was designed and tested for.

If a box is intended for transporting a hot pizza, that doesn't automatically mean it has been tested for prolonged microwave heating.

Is the ink on a pizza box dangerous in a microwave?

It depends on the packaging.

Pizza boxes are commonly printed with branding, cooking instructions, promotional messages and other graphics. Packaging inks are therefore another material that needs to be considered when assessing food-contact safety.

The research supplied for this article cites studies investigating substances including lead and cadmium in paperboard packaging and inks, as well as their potential migration into food.

This doesn't mean the printed logo on your pizza box is automatically toxic.

Modern food packaging is subject to food-contact requirements, and manufacturers need to ensure their materials are appropriate for their intended use.

But microwave suitability is a separate question.

A box being suitable for carrying a hot pizza doesn't necessarily mean that every component of that box has been tested for microwave heating.

What do microwave manufacturers say?

This is perhaps the simplest practical answer.

The research reviewed for this article cites Whirlpool's safety guidance, which recommends removing food from cardboard containers and putting it on a microwave-safe plate.

The principle is straightforward:

Use containers specifically intended for microwave heating.

That is much better advice than trying to determine whether a particular takeaway box contains the right type of cardboard, ink or coating.

What do pizza companies recommend?

Interestingly, major pizza brands don't generally tell customers to microwave leftover pizza inside the original delivery box.

Pizza Hut's reheating advice recommends putting pizza on a microwave-safe plate. The research also notes a technique involving a small cup of water alongside the pizza and heating at reduced power for a short period.

This has an additional advantage:

Your pizza will usually taste better.

Cardboard isn't designed to give pizza a crisp base during microwave reheating.

The microwave heats the water in the food, which can leave the crust soft or chewy. A microwave-safe plate gives you a cleaner, simpler reheating setup.

If you want a crisp crust, an oven, skillet or air fryer is generally a better choice.

So, can you microwave a pizza box for 30 seconds?

This is one of the most common questions.

You may hear people say:

“I've done it for 30 seconds and nothing happened.”

That may be true.

But “nothing happened to me” isn't the same as “this packaging is microwave-safe.”

A short heating period may not produce visible problems, particularly if the box is plain and contains no metal. But consumers generally don't know exactly what materials, coatings, inks or adhesives are present in a particular box.

The safer rule is:

If the box doesn't say it is microwave-safe, take the pizza out.

Thirty seconds saved isn't worth risking a damaged microwave or a packaging-related fire.

Can you microwave an empty pizza box?

You shouldn't.

An empty box contains little or no moisture from food to absorb microwave energy. Dry packaging can therefore heat differently from packaging containing food.

Never use an empty cardboard pizza box as something to “test” in the microwave.

And never leave a microwave unattended while heating questionable packaging.

What if the pizza box has a metal handle or staple?

Take it out of the microwave.

Metal can cause arcing inside a microwave. Depending on the object and microwave design, this can create sparks and potentially damage the appliance or start a fire.

The research specifically identifies metal fasteners and similar components as one reason manufacturers advise against placing cardboard food containers in microwaves.

The better way to reheat leftover pizza

If you have leftover pizza, there are several better options.

1. Microwave  fastest

Put the pizza on a microwave-safe plate.

Heat it in short intervals and check it between cycles.

For a softer crust, a small cup of water placed beside the pizza can help with moisture during reheating. The research supplied for this article cites Pizza Hut's recommendation of reduced power and short heating periods.

Best for: speed.

2. Frying pan  crispier base

Place the slice in a dry frying pan over low-to-medium heat.

Covering the pan briefly can help warm the toppings while the base crisps.

Best for: crispy bottom without using an oven.

3. Air fryer  crispy and quick

An air fryer can restore some of the crispness that pizza loses in the refrigerator.

Best for: one or two slices with a crisp crust.

4. Oven  best for several slices

For multiple slices, an oven gives you more even reheating and can restore the texture of the crust.

Best for: several slices or when quality matters more than speed.

Pizza box vs microwave-safe food container

The important distinction is intended use.

A food-contact box can be perfectly suitable for transporting a freshly baked pizza without being suitable for microwave heating.

What should pizza businesses do?

The question isn't only relevant to consumers.

For restaurants, takeaways and food-packaging suppliers, microwave suitability should be treated as a packaging specification, not an assumption.

If a box is intended to be reheated, the manufacturer should have appropriate evidence supporting that intended use and the packaging should be clearly labelled.

If the box isn't designed for microwave use, businesses can make the customer's life easier by giving simple reheating instructions:

“For reheating, remove pizza from packaging and place on a microwave-safe plate.”

For packaging manufacturers and food businesses, another important consideration is grease-resistant chemistry.

The industry has increasingly moved toward PFAS-free grease-resistant packaging, with regulatory pressure accelerating that transition. The research supplied for this article notes the EU's Packaging and Packaging Waste Regulation (EU) 2025/40 and its restrictions on PFAS in food-contact packaging from 12 August 2026.

The US has also taken action around PFAS in grease-proof food packaging, with the FDA announcing in 2024 that PFAS grease-proofing substances would be phased out from food packaging.

For packaging buyers, this creates a useful question to ask suppliers:

Is the grease-resistant packaging PFAS-free, and can the supplier provide documentation supporting the claim?

A useful rule for takeaway packaging

Here's the simplest way to remember it:

Hot food doesn't automatically mean microwave-safe packaging.

A pizza box has to survive a hot pizza during delivery.

That's different from being placed inside a microwave and exposed to another heating process.

The same principle applies to takeaway containers, paper bowls, wrappers and other food packaging.

Unless the packaging is explicitly designed and labelled for microwave use, transfer the food to a microwave-safe container first.

What happens if you accidentally microwaved pizza in the box?

Don't panic.

If you've already reheated a slice in its box for a short period and there were no sparks, smoke, burning or unusual odours, there's no reason to assume that you've automatically been harmed.

The sensible thing is simply not to make it your normal reheating method.

Next time:

1. Remove the pizza from the box.

2. Put it on a microwave-safe plate.

3. Remove any packaging, stickers or metal components.

4. Heat in short intervals.

5. Stop immediately if you see sparks or smoke.

This is a much more proportionate response than assuming that every microwaved pizza box creates a serious health emergency.

The Bottom Line: Can You Microwave a Pizza Box?

Generally, you shouldn't.

The biggest issue isn't that cardboard itself is inherently incompatible with microwaves. It's that ordinary pizza boxes are not necessarily designed or tested for microwave heating.

Their construction can involve inks, adhesives, coatings, grease-resistant treatments and, in some cases, metal components. Research has also raised wider questions about substances that can occur in food-contact paper and board, including PFAS and bisphenols.

So the safest approach is remarkably simple:

Take the pizza out of the box and put it on a microwave-safe plate.

You'll reduce the packaging risk, protect your microwave and, if you use an oven, skillet or air fryer, probably end up with a better-tasting pizza too.

For packaging businesses, the lesson is equally straightforward: never assume that a food box is microwave-safe simply because it holds hot food. Microwave suitability should be an intentional, tested and clearly communicated packaging characteristic.

If you're looking for high-quality, food-grade packaging solutions, FreshPack Solutions Ltd offers a wide range of packaging products designed to meet modern food safety and performance standards. Whether you need takeaway containers, food boxes, or custom packaging solutions, choosing reliable, professionally manufactured packaging helps ensure quality, compliance, and a better customer experience.

Frequently Asked Questions

Can I microwave a pizza box for 30 seconds?

It's better not to unless the box is specifically labelled as microwave-safe. Short heating may not cause visible problems, but the packaging may contain materials that haven't been designed for microwave use.

Can cardboard go in a microwave?

Some specially designed cardboard packaging can be microwave-compatible. Ordinary takeaway cardboard should not automatically be considered microwave-safe.

Can I microwave a Domino's pizza box?

Don't assume that a Domino's box is microwave-safe. Remove the pizza and reheat it on a microwave-safe plate instead.

What happens if you microwave a pizza box?

Depending on its construction, it can become excessively hot, scorch, smoke or potentially catch fire. Packaging components such as metal can also cause sparks or arcing.

Is pizza box cardboard toxic?

Cardboard itself isn't inherently toxic. Food packaging is subject to food-contact requirements. However, pizza boxes can contain or come into contact with inks, coatings, adhesives and grease-resistant treatments, which is why packaging should be used according to its intended purpose.

Is it safer to microwave pizza on a plate?

Yes. A microwave-safe plate removes the uncertainty associated with the pizza box and is the recommended approach for reheating leftover pizza.

What's the best way to reheat pizza?

For speed, use a microwave-safe plate and short heating intervals. For a crispier crust, a frying pan, air fryer or conventional oven will generally give better results.