Compression classes explained: which mmHg do you actually need?
Updated 2 September 2026 · 7 min read
For prevention — travel, standing work, tired or heavy legs, pregnancy swelling — choose class I (15–21 mmHg). For a diagnosed condition — varicose veins, post-thrombotic care, lymphoedema — class II (23–32 mmHg) is the European clinical standard, ideally confirmed by a phlebologist. Higher pressure is not better; the right pressure worn daily is.
What mmHg actually means
Compression is measured in millimetres of mercury (mmHg) — the same unit as blood pressure — and always at the ankle, where the pressure is highest. A graduated stocking then releases that pressure up the leg: by the manufacturer's certified profile, the area just above the ankle keeps 70–100 % of the ankle pressure, the calf 50–80 %, and the thigh section of longer styles 20–60 %.
This gradient, not the squeeze itself, is what supports venous return toward the heart. It is also why sizing runs by ankle and calf circumference in centimetres — a stocking that does not match your measurements cannot deliver its declared pressure.
The European classes
Piumella carries class I and class II — the two classes that cover everyday prevention and the most common diagnosed conditions. Class III belongs in a specialist's fitting room.
| Class | Pressure at ankle | Typical use | Prescription |
|---|---|---|---|
| Class I | 15–21 mmHg | Heaviness, flights, desk days, light swelling, pregnancy | No |
| Class II | 23–32 mmHg | Diagnosed varicose veins, post-thrombosis care | Recommended |
| Class III | 34–46 mmHg | Severe chronic insufficiency — specialist fitting; not in our range | Yes |
Class I vs class II — the honest difference
If nobody has diagnosed you with anything, class I is almost always the right start. It is significantly easier to put on, comfortable through a ten-hour day, and clinically meaningful for prevention.
Class II earns its extra pressure only when a condition calls for it. Worn on a healthy leg, it is simply harder work for no added benefit — and a stocking that fights you every morning is a stocking that ends up in a drawer.
When to talk to a doctor first
Compression stockings are certified medical devices, and a few situations call for medical guidance before wearing them: peripheral arterial disease, diabetes with nerve damage (neuropathy), acute phlebitis or suspected thrombosis, open wounds or skin infections on the leg, and decompensated heart failure. If any of these apply, see a physician first — and if class II was recommended to you, a phlebologist can confirm both the class and the length.
Frequently asked
Are US “20–30 mmHg” and EU class II the same thing?
Close, but not identical. US ranges are marketing conventions, while EU classes are defined by standards such as RAL-GZ 387 and measured at certified test institutes. EU class II (23–32 mmHg) overlaps the US “20–30” range.
Can compression stockings be harmful?
Correctly sized and worn on healthy skin, no — the pressure is engineered and certified. Problems come from wrong sizing, rolling the top down (which doubles pressure in one band), or wearing compression against medical advice with arterial disease, neuropathy or acute thrombosis.
Do I wear them at night?
No. Lying down, your veins do not fight gravity, so compression brings no benefit and only unnecessary pressure. On from the morning, off in the evening.
