Manufacturing
Compression Socks Explained: mmHg Levels, Fibre Blends and Sizing
What mmHg actually measures, how graduated pressure is knitted, which fibre blends work, and how to size a compression program correctly.
What mmHg Means
Compression is measured in millimetres of mercury (mmHg). The number describes how much pressure the sock applies to the leg, and it is always stated as a range because pressure is highest at the ankle and decreases as the sock rises up the calf. That gradient, not the tightness of the elastic, is what defines a graduated compression sock.
The commercial classes are usually grouped like this: 8–15 mmHg for light everyday support, 15–20 mmHg for moderate support, 20–30 mmHg for firm support, and 30–40 mmHg for the higher medical classes. Buyers should choose the class from the wearer and the use case — cabin travel, long shifts, training or recovery — rather than from the price point, because a class that is too light will not feel supportive and one that is too firm will not be worn.
How Graduated Pressure Is Knitted
Graduated compression is created during knitting. The machine controls yarn tension across the leg so specific zones are knitted tighter, producing a pressure profile from ankle to calf. This is why compression socks are knitted on dedicated compression machines rather than on ordinary sock machines with more elastic added.
Consistency is the hard part. Two socks that look identical can apply different pressure if the yarn lot, the tension setting or the size grading drifts. A supplier should be able to knit a sample to your chosen class, so your team can check the pressure feel and the fit before bulk production starts.
Fibre Blends: Recovery First, Comfort Second
The base of most compression socks is nylon with elastane, because the knit has to recover its shape after every wash if the pressure class is going to stay stable over the life of the sock. Comfort fibres are blended in around that base.
Natural fibres such as merino wool, bamboo viscose and Tencel can be carried into compression programs for softness, temperature regulation and a more premium hand feel. The blend is normally confirmed per program rather than fixed, because a higher natural fibre share changes how the knit recovers. Ask for a blend proposal against your target class, wearer and wash expectations rather than copying a ratio from another product.
Sizing: Why Calf Circumference Decides
Compression socks are sized by calf circumference, with shoe size as a secondary reference. The same sock that fits correctly on a 34 cm calf will over-compress a 30 cm calf and under-compress a 38 cm calf. That is why a pressure class is meaningless without the size chart it was validated on.
A practical chart uses two or three calf bands plus foot length, and it should be tested across the full size run on a sample order. For wholesale programs, keep the chart stable between reorders — changing the sizing silently is the fastest way to damage repeat business in this category.
Claims, Compliance and What a Manufacturer Should Not Say
Compression garments are treated differently from ordinary socks in many markets, and medical or therapeutic claims are regulated. A manufacturer can describe the compression class, the construction and the fit; claims about treating or preventing a condition belong to the brand that sells the product, and are their regulatory responsibility in each market.
For buyers, the safe path is to keep the product page technical — class, materials, sizing, care — and to let the brand handle any health positioning with its own legal review. A supplier that offers to write medical claims for you is a compliance risk, not a shortcut.
Need Help With Your Sock Line?
Tell us what you want to make and we will help you shape the right spec.
Get a Quote