Can Legos Melt in a Hot Car? (When Do They Melt?)

Last updated on September 14th, 2022 at 08:45 pm

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Last updated on September 14th, 2022 at 08:45 pm

People of all ages and from all walks of life are fond of Legos or at least have played with them at sometime in the past. Legos really do capture the hearts of both adults and kids through the different sets that you can build while playing with them.

Because these toys are quite handy and fun to bring to virtually any place that you are traveling, they are sometimes left or stored just pretty much everywhere.

However, not all locations have good temperatures for toys to be left, especially those toys that are more vulnerable with delicate build qualities. But, are Legos really that easy to destroy? Will they actually melt in a hot vehicle?

Legos do not usually melt under normal circumstances and they also will not melt inside of a hot car, however, when they are stored in extreme heat the material can start to soften and the Legos can become deformed. This is what will happen if they are left in an extremely hot car. They will not melt but they will become deformed and will become unusable for normal building. 

The type of brick material that they are made of is the first factor that determines the tendencies of a Lego to melt. In the rest of this article I will go into more detail about how hot it has to be to actually melt the Lego blocks as well as some storage tips that will help you keep your Legos in great condition for many years to come. 

What Is The Melting Point for Legos?

Some people melt their Lego toys for arts and crafts purposes or just to see what happens. But unless you are planning to get a little artsy with such a toy, seeing them becoming deformed in your car is a sign of a pretty bad day.

You can keep your Legos safe from future tragedies by knowing the quality of your Lego’s material, design, and structure as well as knowing exactly what temperatures that they can handle. 

Legos are primarily composed of two types of materials: Polycarbonate plastic and Acrylonitrile Butadiene Styrene or ABS. Manufacturers will typically choose ABS over polycarbonate plastic since the toys that are produced from this material are easier to color. ABS Legos will reach a basic melting point at 221⁰F (105⁰C). 

Obviously, the inside of your vehicle will not reach this temperature (unless you are driving near the sun!) but Legos can start to deform at 130-140 degrees Fahrenheit and that is a temp that the inside of your vehicle can easily reach. 

On an 85 degree day the inside of your vehicle can reach temperatures of 130 degrees after just two hours! That is enough for the Legos to start deforming which in turn will make them useless! So if the outside temperature is above 85 degrees then you should NOT leave your Legos in your car!

How ABS Legos React to the Heat 

Here is a comprehensive table of how Legos react to heat:

⁰F ⁰C State of Legos

<131 <55 No changes, durable

131 55 Malleability; weakening of the brick structure

176 80 Bricks still hold structure even under pressure

185 85 Visible deformations occur

221 105 Lego melting point

248 120 Mild smoke release

257 125 Discoloration of the bricks

284 140 Bricks are severely deformed; emit heavy smoke

320 160 Begin to take a sheen as it liquifies

>752 >400 Potentially releases cancer-causing agents; pose a health risk

As can be seen from the information above, the Legos have to heat up quite a bit before they begin melting but the deforming process starts significantly earlier. 

Will Legos Melt in the Attic?

An attic is a popular place to store old toys and since Legos have been around since the 1930s there are likely many people who have stored their Legos or have at least considered storing them in their attic. 

If you store your Legos in your attic will they melt up there though? 

Even in the hottest areas of the USA (Phoenix/Las Vegas) attics will rarely get over 130-150 degrees so although Legos are unlikely to melt in the attic they are at risk of becoming deformed if you live in a place with an extremely hot climate. 

The only way to know for sure is for you to put a thermometer in your attic during the hottest time of the year and see what temperatures your specific attic will reach. Since an attic’s temperature varies based on the materials used on the roof, how much sun it receives, etc. two attics right next to each other could have far different temps inside their attics. 

If your attic is unventilated, has active equipment, and has no cooler temperatures at night, it can possibly reach the peak of 150⁰F (65.5⁰C) during sunny days such as those in Phoenix or similar areas. 

Such temperatures are lower than the standard melting point of 221⁰F (105⁰C) but are higher than the temperature where they will start to become deformed. Lego bricks are best placed in an area with temperatures lower than 113⁰F (45⁰C) so your attic is not a good choice unless you live in an area that doesn’t get extremely hot during the summertime. 

Before storing your Lego collection in your attic, make sure to check its ventilation, heat source, sunlight exposure, and the highest temperature of the storage space. It is much better to just purchase a cheap thermometer and check it during the hottest time of the year than it is to come back from your legos only to have them warped and be unable to use them. 

ABS structure is prone to deformation when heated but experts say that even though the Legos may change their form from being stored at higher temperatures, bricks rarely appear completely melted. 

How long will Legos last?

Having mentioned how Legos will melt only at extremely high temperatures and besides that they certainly seem to be indestructible (you will especially feel that way if you have ever stepped on one) you might be wondering how long you could expect Legos to last. 

Although the jury is still out on an exact lifespan of Legos there is some data that suggests they could last hundreds and hundreds of years even in harsh elements. 

Based on a study published in Science Direct Legos will last 100-1,300 years before they decompose in the ocean. Since they are made of ABS plastic they are likely to NEVER decompose on land though! 

That means that it is possible that 1,000 years from now people will still be stepping on your children’s Legos!!!

Ok, all joking aside, Legos will last multiple generations which is why the price that you pay for them really isn’t too bad when compared to how many years, decades, and even centuries, they can be used for! 

Storage Ideas for Lego Toys

To help protect your Legos from the elements (or from being stepped on/lost) it’s important to have some good storage options/ideas available to you. Some of the more popular ways to store your Legos are: 

Storage with buildable top

This table-like storage bin is designed to help kids organize their Lego pieces after playing without exerting a huge effort.

The bin has a tabletop that is wide enough for building different forms and allows kids to have enough space when playing with siblings and friends.After playtime, they can just store the pieces below the tabletop where there are two compartments for the toys.

If you have the space then this is really the ideal storage option as it keeps all of the Legos in one location while also making it really easy to build/store them when needed. 

A Drawstring Bag 

A bag is a great alternative for moms and kids who want to skip the hassle of picking up the scattered Legos and putting them inside of the specific container. With a drawstring bag you simply lay the bag down next to the Legos and scoop them inside. 

This makes cleaning up the Legos far easier however it also means that to play with just a few Legos you have to dump out the entire bag so that you can see where all of the pieces are that you need. 

Sorting trays

Trays never get old! Kids and collectors alike will often get great satisfaction when organizing the Lego pieces in a sorting tray.These trays are mostly able to fit regular-sized Lego models and sorting trays allows kids to organize the pieces according to colors or shapes if they choose as well. 

Sorting drawers 

If you have bigger Lego pieces, then sorting drawers would be an ideal choice to stay well-arranged and tidy. Sorting drawers are perfect for individuals who are continuously leveling up their serious passion for building larger sets as you can use a drawer for each set or just for certain parts. 

The tiny drawers can appear as a nuisance to the eyes, but the small compartments are a must to store the smallest Lego bricks and prevent them from becoming lost in between builds. 

Labeled Bins

Be more organized than ever with labeled bins. With this storage option, you can separate the Legos for trains, games, tools, etc.You can also organize the pieces by size, color, material, and other sorts of Lego classifications. 

The biggest pro to using bins is that they are cheap and can be purchased in all kinds of shapes and sizes so as your Lego collection grows, so too can you bins. 


Legos can deform and lose their original colors/shapes when exposed or stored in an extremely hot environment, whether that is inside a car, in the attic, or just left outside on the BBQ grill. Most of the time Legos won’t actually melt but a deformed Lego is about as worthless as an entirely melted one so you will want to make sure to avoid leaving your Legos anywhere that they could get too hot! 

Proper care and responsible storage are the main keys to maintaining the good condition of your Legos. 

Last updated on September 14th, 2022 at 08:45 pm

Matthew R

Hi, My name is Matt and I am all about toys! When trying to find accurate information online about toys I was finding it difficult so I decided to make this site.

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