Can You Microwave Pyrex?

Pyrex is the name of a brand that makes glass cookware, but any type of glass can be used in the oven or microwave. Some people say that it’s okay, but others hold strong opinions against microwaving anything made out of Pyrex.

The short answer is Yes, but only pieces specifically created for the purpose of cooking in a microwave oven– otherwise, no ..

We’ve done some research and found some interesting things about Pyrex, both good and bad! So before further ado, lets get started.

Pyrex and its composition

The terms “pyrex” and “borosilicate glass” are often used interchangeably, but this is incorrect. Pyrex is just one brand of borosilicate glassware, so it’s important not to use the term “pyrex” when referring to other products made from borosilicate glass.

For example, Pyrex bakeware has tempered rims to help alleviate thermal stress caused by expansion and contraction.

Pyrex is typically composed of approximately 88–91 percent silica, 7–9 percent boron oxide (borax), and 2–4 percent alumina , by weight.

In addition to these components, Pyrex bakeware contains less than one percent calcium oxide and sodium oxide by weight.

Pyrex is more resistant to shattering than typical borosilicate glasses due to its tempered rims, so you shouldn’t risk using other types of borosilicate glass in the oven or microwave.

To avoid cracking or shattering your bakeware when using it in the oven or microwave, simply follow the recommendations from the manufacturer that came with your product but pyrex is safe for use in microwaves .

How long can you microwave Pyrex?

Considering how long Pyrex has been around, people have been microwaving it for a long time. There is no specific answer to how long you can microwave pyrex, and the length of time varies due to many factors: size of dish and power output (watts or strength) of microwave. 

Generally speaking, if your microwave wattage is greater than 700 watts, then you should be fine microwaving your Pyrex dishes as much as you want, unless there are cracks in the glass that could lead to overheating during cooking.

Does that mean that all Pyrex is meant to be microwaved? No – some pieces say on the bottom not to put in the microwave. Good rule of thumb though is if it’s glass ovenware safe at 350F or 375F, it’s oven/microwave safe.

The answer to how long can you microwave Pyrex is that if your dish doesn’t have any cracks or chips in it, then there is no danger of the glass shattering when microwaved. 

Heating glassware presents an interesting problem – while some materials soften gradually with temperature increases, glass may soften suddenly and without warning causing possible injury. 

This means that it’s not a good idea to test this on your own by putting your hands in the microwave while heating up some Pyrex!

Can you microwave pyrex?

Tips to microwave Pyrex

1. The manufacturer of Pyrex says that they honor warranties only if the microwave is used and cleaned properly. So keep this in mind when you’re ordering a dish from your favorite online retailer.

2. Only heat glass containers that have two handles or that can withstand excessive heat. This means that there’s no need to reheat those single-handled yogurt glasses as long as you don’t use too much voltage on them…

3. Always place glassware as far away from open walls as possible. Don’t place a glass bowl on the turntable, but instead use a microwave safe plate or saucer to support it.

4. Once you’ve heated glassware in the microwave, let it sit outside of the microwave for at least 5 minutes before you attempt to remove it from the turntable by holding its edge(s). 

The reason for this is that there’s still some heat inside that needs to dissipate into other parts of the Pyrex vessel. This prevents burns and broken glasses when transporting hot Pyrex .

5. You can test your Pyrex plates by running water over them in 80-100% power mode. If they’re microwavable, then they should be just fine when you’re heating the food.

6. If there are any defects in your Pyrex plate, dish or bowls, stop using them! It’s not worth the risk of breakage to use something with a crack.

7. Never use a cover on top of your microwaved pyrex , no matter how big or small/thick the bowl is! This can cause uneven heating because microwaves don’t penetrate metal very well.

Is Pyrex microwave safe?

If you have ever used a glass pyrex dish in the microwave, you might have wondered if it was really safe. 

This is especially true if you are using old pyrex dishes that may be chipped or cracked. 

The answer isn’t as simple as yes or no, but the manufacturer claims that the oven-safe glass is 100% safe for use in microwaves. It can handle temperatures up to 500F which is probably hotter than what most people use their microwave ovens for!

Pyrex ceramic is 100% microwave safe

The question of whether or not pyrex glass is microwave safe has been raised periodically during the past forty years since it was invented, but for many reasons this subject has received very little scientific scrutiny. 

There have been no published studies that have taken a scientific look at the issue of using old-style glass pans in microwaves. The manufacturer claims that they are completely microwave safe, and although they do not recommend putting them into an oven or under a broiler – which they consider to be misuse – there seems to be no reason why you wouldn’t feel confident about using your own personal pyrex dishes and bowls in the microwave oven.

In fact, it is probably safer to use them in the microwave rather than putting them directly under a broiler, where a sudden flare-up could send a molten glass fragment flying before you had time to react.

At first glance there seems to be no reason why Pyrex should be any more likely to explode when heated in a microwave oven than other kinds of glass dishes – and yet accounts have been gathered from all over the world which indicate that many people do not agree with the manufacturer’s claims that pyrex cookware is safe for microwave cooking.

Will cold Pyrex break in microwave?

Yes, it’s true that cold pyrex will break in the microwave. The glass used for this brand of cooking ware cannot resist rapid changes in temperature and so is harder than most types – making them more susceptible to melting if heated unevenly or intensely enough!

The use of Pyrex or any glass bakeware is not recommended for dishes that require extreme temperatures. 

For example, it’s unwise to put very hot food in a cold oven and vice versa since sudden changes may cause the utensil to shatter or break on you!

Pyrex bowls are fragile, but the reward for their fragility is that they can withstand quite a lot of abuse. If you’re heating or cooling your bowl too quickly, it might just break in an instant with no warning at all!


If you are not sure whether or not your pyrex is safe for microwaving, the best bet would be to avoid it. Use other alternatives like ceramic containers that are specifically designed to withstand microwave exposure. 

If you do use something that was meant for the oven, follow the guidelines shared above and exercise caution to prevent injury.

I hope this helps! I know it’s confusing because there are so many different opinions on this subject, but microwaving anything without first checking if it’s microwave-safe can lead to serious injuries .

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I was always into cooking and kitchen stuff as a kid. My mom would often find me in the kitchen, helping her cook dinner. I loved being able to create something delicious that everyone could enjoy. So when I grew up, I decided to start my own blog. I love being able to share my culinary creations with people all over the world!

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