Casper mattress ILD for each layer?

I´m new to the blog and really overwhelmed with the amount of information here :cheer:
I want to buy a Casper Mattress, thanks to the blog most of my questions were solved. The only thing I couldn’t find was the ILD for the polyurethane support layer and the memory foam. I know the top latex layer has a 13 ILD.

Latex: 13 ILD
Memory Foam: ?? ILD
Polyurethane support foam: ?? ILD

If someone can help me with this info that would be awesome! Thanks

Hi csalinas.m26,

ILD is only one of several specs that makes one material feel softer or firmer than another (see post #4 here) and the ILD of different materials or different types and blends of latex also aren’t directly comparable to each other anyway.

Different people can also have very different perceptions of firmness and softness compared to others as well and a mattress that is firm for one can feel like “medium” for someone else or even “soft” for someone else (or vice versa) depending on their body type, sleeping style, physiology, their frame of reference based on what they are used to, and their individual sensitivity and perceptions. This is all relative and very subjective and is as much an art as a science. There are also different types of firmness and softness that different people may be sensitive to that can affect how they “rate” a mattress as well (see post #15 here).

Unless you have a great deal of knowledge and experience in the industry with different types of mattress materials and components and their individual specs and know how different layering combinations and mattress designs feel to you when you combine different layers with different properties together in different ways and you can accurately translate all this complex information into your own “real life” experience that can be unique to you … I would tend to avoid using complex specs to try and predict how a mattress will feel or perform. When you try and choose a mattress based on complex combinations of specs that you may not fully understand or based on specs for single layers that are only part of the picture and that may not be as relevant or meaningful as you believe they are … then the most common outcome is “information overload” and “paralysis by analysis”.

I would always keep in mind that no matter how many specs you know about a mattress or how much you try and “analyze” specs to try and predict how a mattress will feel … the only way to really know how any mattress will feel to you as a whole will be based on your own personal testing or your actual sleeping experience.


Thanks for the quick reply Phoenix.
I completely agree, you have to try a mattress and decide if its good for you .

Regarding my question, its only out of curiosity, I already know I´ll buy the Casper. I you happen to know the ILDs for each layer it would be great.


Hi csalinas.m26,

This is the type of “curiosity” that can end up turning “simplified choice mattresses” into “overwhelmingly complex choice” mattresses. The problem is that if a manufacturer provides this type of information to the 99% of their consumers that don’t understand that it’s basically meaningless it would only encourage them to believe that they can use the information to make comparisons between mattresses when they can’t.

The ILD ranges of the synthetic continuous pour latex that Casper uses in the top 1.5" of the mattress doesn’t correspond to the ILD ranges of other types and blends of latex so it can’t be used to make meaningful comparisons with other types and blends of latex or even other layers of the same latex that are a different thickness.

The IFD/ILD of memory foam is also very misleading because IFD testing produces different results for memory foam than it does for other more resilient materials and the IFD of memory foam also changes with temperature, humidity, and the length of time the memory foam is continuously compressed. The firmness/softness of memory foam will also vary with the specifics of the chemical formulation for the memory foam that affect its temperature sensitivity and its response time not to mention the thickness of the memory foam layer and the type and thickness of the layers above it.

The polyfoam base layer would be in a firmer range but how much the IFD of the polyfoam base layer affects the “feel” and firmness of the mattress as a whole will greatly depend on the type and thickness of the layers above it. A “typical” IFD for a base layer would be somewhere in the range of 28 - 32 but it could be softer or firmer depending on the design goals of the mattress. I would also keep in mind that IFD testing on polyfoam uses a 4" layer of foam while ILD testing on latex is generally done on a 6" core of latex so once again the ILD/IFD testing will produce different results (Polyfoam IFD’s are generally firmer than the same ILD with latex).

If I was a manufacturer or retailer in most cases I probably wouldn’t provide this information to my customers because most manufacturers or retailers would be well aware that if they do provide it to their customers the temptation would be too great to try and use it for making comparisons and any knowledgeable retailer or manufacturer would realize that this would be much more misleading than helpful and their customers would probably end up choosing a mattress for all the wrong reasons.

While I don’t know the ILD/IFD of all the foam layers in the Casper … a quick phone call would be the most reliable source for this type of information if they provide it to their customers.


Phoenix, thank you so much for the reply. Interesting point of view, makes sense.