Foam grades in Australia

I spent many months reading this forum sometime ago before I purchased my new mattress, the information here is priceless and I wish to thank all the contributors for their generosity - you guys are helping America to sleep!
I’ve recently moved to Australia and thought of this forum after my first attempt to buy a new mattress here - the issue that I have is this: mattress sellers here use a different grading system for the firmness of foams. Obviously, they use the metric system instead of imperial but it’s easy enough to figure out foam density by converting lb per cubic foot to kg per cubic meter. But figuring out the firmness is a whole new ball game - Instead of the ILD system that I have educated myself about in the past, the system here is a way of measuring the amount of force in Newtons that is needed to compress a piece of foam to 40% if it’s original height.
Can anyone suggest a way to convert the ILD system into the Newtons system that I’ve mentioned above so that I can use my old education to buy a mattress over here? Any advice would be much appreciated folks!

Hi janey222,

Welcome to the Mattress Forum! :slight_smile:

The last time I was asked this I think was in 2013. I discuss it a bit more in post #2 here. Because the methods for testing are different in Australia (we test 25% compression for ILD in North America), their numbers, even when converted, would be higher and not directly relatable. My best recommendation (as in the post I linked to) is to use your own personal experience when evaluating a mattress and then use that as a reference for your “comfort spec”.

European Bedding has some good information about pascals here for latex. In general, they say a soft latex mattress is around 3.5 kPa (kilo-Pascal), a medium around 4 and a firm around 4.5. They also have a chart on that page relating ILD to kPa which you may find interesting.