Why Do Glass Plate Break in the Microwave?

Ever popped a glass plate in the microwave and then, ‘KABOOM’, it shattered into a million pieces?

What a mess, right?

Well, there’s some pretty cool science behind why that happens, and it’s not just because your microwave has a bad temper.

Let’s break it down (no pun intended) and understand why glass plates sometimes break in a microwave.

Why Did the Glass Plate Break in the Microwave?

There could be a couple of possible reasons for this. Let us explore each one separately.

Material Not Compatible

One reason could be that the glass plate was not specifically designed for microwave use. 

Not all glassware is suitable for microwaving. Thermal stress can play a role in causing a glass plate to explode. 

Glass plates expand and contract with temperature changes. If the material can’t handle the rapid fluctuations in temperature that microwaving can cause, it results in the glass plate breaking.

To avoid this issue, always ensure you are using tempered or heat-tolerant glasses like Pyrex.

Uneven Heating 

Another possible cause is uneven heating. Microwaves heat food by emitting waves that bounce around and get absorbed by the food. 

If there is a large area of your plate not covered by food, the microwaves may reflect off the surface, causing the glass to heat up and crack. 

To minimize this risk, spread your food evenly on the plate, and avoid using the microwave’s highest setting if possible.

Cracked or Chipped Plate

Accidents can also happen in the kitchen. Your glass plate might have had an unnoticed chip or crack before you placed it in the microwave. 

The stress caused by heating can cause an already weakened plate to break. So, always inspect your glassware for any signs of damage before using it in a microwave.

Popcorn Bags

Using microwave popcorn bags could sometimes cause breakage of the glass plate too. The expansion of the bag might put pressure on the plate, leading to cracking or breaking. 

In such cases, follow the packaging instructions, which may recommend placing a plate under the bag for proper popping.

Old Age 

The age of the plate plays a role in its resistance to heat.

As a plate gets older and is repeatedly exposed to heat, it becomes more susceptible to cracking or breaking.

Too Much Weight 

When the plate is carrying too much weight, it can also contribute to breakage. 

When you place a lot of food on your plate, particularly heavy or dense items, the weight can put extra stress on the glass, heightening the risk of it breaking in the microwave.

For more details, watch the video below: 

Also read: Difference Between Oven and Microwave?

Precautions to Take While Using a Glass Plate in the Microwave

Using a glass plate in your microwave can be a safe and effective way to heat your food.

However, it is important to take some precautions to avoid any accidents or breakages.

Firstly, always make sure that your glass plate is microwave-safe. This is important because not all glassware is designed to withstand the heat and pressure generated by microwaves. 

You can usually find the “microwave-safe” label on the bottom of the glass plate or in the manufacturer’s instructions. In case you’re unsure, avoid using that plate in the microwave.

When heating your food, do not overheat the glass plate. Remember that the purpose of the plate is to distribute heat evenly, so excessive microwave use can cause the plate to break. 

It’s a good idea to regularly check your food as it heats to prevent the plate from getting too hot.

Be cautious about using a glass plate with any cracks, chips, or damaged edges. These imperfections can weaken the plate, which can lead to breakage while in the microwave. 

Replace any damaged plates, as their continued use may cause further damage or potential injury.

Always use oven mitts or a towel when removing the glass plate from your microwave. Glass plates can become extremely hot and could burn your hands. 

Moreover, handle the plate carefully to avoid any accidental drops or impacts that could lead to breakage.

To summarize, to use the glass plate in your microwave correctly, follow these steps:

  • Place the glass plate on the turntable of your microwave, ensuring that it’s centered and stable.
  • Put your food on the plate, taking care not to overload it or place it unevenly, as this might cause the plate to wobble or tip over during cooking.
  • Set the appropriate cooking time and power level for your specific dish. 
  • Refer to your microwave’s instruction manual or look for guidelines online if you’re unsure about the settings.
  • Once your food is cooked, carefully remove the glass plate from the microwave using oven mitts or a towel. Always check that the plate is not too hot to handle before doing so.
Also read: Can you Microwave Tupperware?

Plates That Are Safe for Microwaving

When using your microwave, it’s important to choose the right type of plates to ensure they’re safe and prevent damage. 

Here’s a list of plates that are safe to use in the microwave:

Glass Plates (Borosilicate glass or Tempered glass)

Glass plates, such as those made from borosilicate glass or tempered glass, are a popular choice. 

They’re safe for microwaving because they can handle high temperatures and resist cracking or shattering. 

Just make sure the glass doesn’t have any metallic paint or inlays, as these can cause problems in the microwave.

Also read: Are Mason Jars Microwave Safe?

Ceramic Plates

Ceramic plates, like those made from porcelain or stoneware, are another excellent option.

They’re microwave-safe because they can withstand heat exposure and won’t get damaged easily. 

Be sure to avoid using any ceramic plates with metallic decorations or glazes, as these can cause sparks or damage in the microwave.

Also read: Can Ceramic Cookware Go in the Oven?

Plastic Plates

Not all plastic plates are suitable for microwaving, but those labeled as “microwave-safe” are safe to use. 

These plates are made from materials that don’t break down, melt or release harmful chemicals when heated in the microwave. 

Always check for the microwave-safe label when using plastic plates.

Also read: Can You Put Plastic Bag in Microwave?

Microwave-Safe Paper Plates

Paper plates that are specifically labeled as microwave-safe are a convenient option for quick meals and easy clean-up. 

They’re microwave-friendly because the material is designed to tolerate heat and not catch fire or get excessively soggy.

Also read: Can You Microwave Paper Plates?

Plates That Are Not Safe for Microwaving

As a microwave user, you should be aware of the types of plates that are not safe for microwaving. 

Knowing this information will help you avoid accidents and ensure that your food is heated properly.

Metallic Plates

Plates with metal or metallic paint should not be microwaved.

Metal can cause sparks and even catch fire, posing a risk to your safety and damaging your microwave.

Crystal Plates

Crystal plates usually contain lead, which can damage your microwave and leach into your food.

Avoid microwaving these plates to be on the safe side.

Handmade Pottery

Certain types of handmade pottery may contain materials that are not suitable for microwave use. 

To ensure your safety, check with the manufacturer or maker of your pottery to see if it is microwave-safe.

Plates with Cracks or Chips

If a plate is already damaged, microwaving it can cause additional cracks or even cause it to break altogether. 

Moisture trapped in the cracks can lead to further shattering. It is best to avoid using damaged plates in the microwave.

Plastic Plates Without a Microwave-Safe Label

Certain types of plastic can release harmful chemicals when microwaved. Always look for a “microwave-safe” label on plastic plates before using them in your microwave.

Remember to always be cautious when using plates in a microwave. 

Stick to microwave-safe materials, and you’ll be well on your way to enjoying perfectly-heated meals without any accidents or damage to your microwave.

Also read: Is Pyrex Microwave Safe?

How to Identify a Microwave-Safe Plate

Here are some simple tips that can help you determine if a plate is safe to use in the microwave:

First, look for any symbols or labels on the plate. 

A microwave-safe symbol, usually represented by a microwave icon with wavy lines, indicates that the plate has been tested and is safe for microwave use. 

If you don’t see this symbol, check the manufacturer’s website or packaging information for any safety guidelines.

Next, examine the material of the plate. Ceramics, glass, and plastic are generally microwave-safe materials, as long as they don’t have metallic components or decorations. 

Avoid using plates with gold or silver accents, as these can cause sparks in the microwave.

Keep in mind that not all plastic is microwave safe. 

Look for plastics labeled as “microwave safe” or with a symbol that includes a microwave and a series of numbers, which represent the recommended heat settings for that plastic.

Do a simple test if you’re unsure about a plate’s safety. Fill a microwave-safe cup or glass with water and place it on the plate. Microwave the plate and cup for one minute. 

If the plate remains cool to the touch, it’s most likely microwave-safe. However, if the plate becomes hot and the water remains cool, it’s not safe for microwave use.

Finally, if you have any doubts or concerns, it’s always a good idea to check with the plate’s manufacturer is important to avoid accidents and maintain safety in the kitchen.

Also read: Can You Microwave Ziploc Bags?

How to Clean the Microwave After the Glass Plate Breaks

First, unplug your microwave to ensure safety. Next, put on protective gloves.

The broken glass could be sharp and dangerous, so it’s important to protect yourself before cleaning.

Remove Large Fragments

Start by removing any large pieces of broken glass from the microwave oven. Carefully pick up the bigger pieces and dispose of them in a trashcan. 

Be cautious, and don’t rush, as there might be smaller shards hidden among the bigger pieces.

Broom for Smaller Fragments

After removing the larger fragments, sweep up the smaller pieces with a small hand-broom. 

This will help you collect the smaller glass shards that might be challenging to pick up by hand. 

Gently sweep the broom inside the microwave, paying attention to corners and edges where tiny pieces might be hiding.

Soapy Solution

Once you’ve collected most of the glass shards, take extra care in cleaning the interior of your microwave. 

Wet a soft cloth with warm, soapy water, and wipe the inside of the microwave thoroughly. 

This step not only removes any remaining glass particles but also cleans any residue or food particles that might be present.

Vacuum Cleaner

To ensure that you’ve removed all the small glass pieces, pass a vacuum cleaner over the interior of the microwave. 

Use a narrow nozzle attachment to reach tight spaces and ensure that no glass shards are left behind.

Air Dry

Finally, allow your microwave to air-dry completely before using it again.

This will prevent any moisture damage and ensure that your microwave is clean and ready for use when you need it. 

Also read: Is Melamine Microwave Safe?

Frequently Asked Questions

Here are some frequently asked questions:

Are Microwavable Plates Prone to Cracking?

Some microwavable plates can be prone to cracking, mainly due to the type of material they are made of.

Certain materials may have trouble handling the heat and electromagnetic waves in the microwave, causing them to break or melt.

To reduce the risk of cracking, choose microwave-safe plates and avoid using materials not recommended for microwave use.

How Do I Properly Place the Glass Plate Inside the Microwave?

To properly place the glass plate inside the microwave, ensure that the plate is clean, dry, and free from cracks or chips.

Align the plate’s center hole with the microwave’s turntable roller guide.

Gently lower the plate onto the guide, making sure it fits snugly and rotates smoothly. Improper placement may lead to uneven heating or possible damage to the plate.

Can I Warm a Glass Plate in the Microwave?

You can warm a glass plate in the microwave as long as it is specifically labeled as microwave-safe.

To check if a glass plate is safe to use in the microwave, perform a simple test.

Place a cup of water on the plate and microwave it for one minute. Carefully touch the plate – if it’s just slightly warm, it’s safe to use

Also read: Can You Reheat Tea In Microwave?


In conclusion, your microwave’s glass plate can break for a variety of reasons. One common cause is exposure to high temperatures. 

Microwaving a plate for too long or at a high temperature can cause it to warp, leading to breaking. Another reason might be the age of the plate or the material it’s made of.

It’s important to avoid using cracked or chipped plates, as these are more likely to break during the heating process. 

Additionally, sudden temperature changes, like adding cold food to a hot plate, can stress the material and cause breakage.

To prevent microwave plate breakage, it’s best to use microwave-safe materials like ceramic, glassware, plastic, and stoneware plates. 

When your microwave’s glass plate breaks, make sure to replace it with the same plate from the manufacturer for optimal performance.

Following these simple tips can ensure a safer, more enjoyable microwaving experience. Enjoy your perfectly heated meal!

Other articles you may also like:

I’m Jueria and I am a regular contributor on cookeryspace.com. In my articles, I share time-saving techniques, appliance wizardry, and health-friendly recipes to bring taste and wellness to your table. So raise a glass (or a spatula) with me, to good health and good food, made easy!