Ask two latex suppliers for a “medium” layer and there is a good chance you will receive two different products. Both suppliers will be telling the truth. Each one is describing a position within its own range, and there is no shared industry definition that ties the word “medium” to a fixed figure. For a mattress brand or manufacturer, that gap between the word and the product is where most firmness problems in a new build begin.
Why Firmness Words Drift
Firmness words are relative. A brand that makes mostly plush products may call something medium that a brand known for firm, supportive builds would call soft. A supplier whose range starts at a very soft grade will place its midpoint differently from one whose range starts higher. Neither is wrong. They are simply measuring against different starting points.
There is a second source of confusion. The firmness label on a finished mattress describes the whole construction: every layer, the cover and the way they work together. When a customer says their current mattress is “medium,” that tells you very little about the firmness of any single latex layer inside it. A medium mattress might contain a soft comfort layer over a firm core, and still feel medium overall.
For marketing a finished mattress, that flexibility is useful. For ordering a component, it is a liability.
ILD Is the Common Reference
ILD, or Indentation Load Deflection, measures how much force it takes to compress a foam sample by 25 percent of its thickness under a standardized test. A higher number means more force is needed, so the foam feels firmer. We cover the test itself in more detail in ILD Explained: How to Choose Latex Firmness.
What matters here is that ILD is a measurement rather than a description. Two suppliers may disagree about what “medium” means, but if both quote an ILD of 26, they are talking about comparable resistance under the same test. That makes ILD the only figure that travels reliably between your design team, your supplier and your production line.
Our Firmness Scale
We supply natural latex across five firmness levels, each tied to an ILD range and a density grade:
| Feel | ILD Range | Density |
|---|---|---|
| Extra Soft | 12-20 | D55 |
| Soft | 18-23 | D65 |
| Medium | 24-29 | D75 |
| Firm | 30-37 | D85 |
| Extra Firm | 38-45 | D95 |
The ranges overlap slightly at the edges, which is normal in foam production. Firmness sits on a continuous scale, so a piece at ILD 19 could reasonably be described as either Extra Soft or Soft. That overlap is one more reason to order against the number rather than the name.
How to Write a Firmness Specification
When you place an order, a firmness specification should include:
- A target ILD, not only a feel name. For example, “ILD 26” rather than “medium.”
- An accepted tolerance, such as plus or minus a few points, agreed with your supplier before production.
- The layer it applies to, since a comfort layer and a core in the same build will have different targets.
- The thickness, because the same ILD feels different in a thin layer than in a thick one.
If you already use a feel name in your own product range, keep it for your customers, but map it internally to an ILD target. That way “our medium” means the same thing on every purchase order, regardless of which supplier fills it.
Translating What Customers Ask For
Brands often receive requests like “the same as our current medium, but a little softer.” The practical way to handle this is to find out the ILD of the layer you are currently using, then move down within the scale from there. If you do not know the current figure, ask your existing supplier for it, or have a sample of the current layer tested.
Once you have a starting number, small adjustments become predictable. Moving from ILD 28 to ILD 24 is a clear, deliberate step. Moving from “medium” to “medium-soft” is a guess.
Confirm With Samples
Even with a precise ILD target, it is worth feeling the material before you commit to a production run. A number describes resistance under test conditions. A sample shows how it feels in your prototype, with your other layers and cover.
A useful approach is to request samples from two or three adjacent bands on the scale, for example Soft, Medium and Firm, and compare them side by side. The differences between neighbouring levels are often clearer in hand than on paper, and the comparison gives your team a shared reference for future orders.
Specify by Number, Sell by Name
Feel names are part of how you present a product to customers, and there is nothing wrong with using them. The key is to keep them on the marketing side. On the supply side, every layer should be ordered against an ILD target and tolerance, so what you receive matches what you designed.
Feel the difference between the levels yourself. Request a Free Sample across the ILD range you are considering, or request a quote if you already have your target ILD.