Compression Sock Level Selector
Compression socks come in graduated strengths measured in mmHg. The right level depends on why you want them. Pick your main reason for a typical range — and a clear flag for when you should ask a doctor first.
The compression levels explained
| Level (mmHg) | Strength | Typical uses |
|---|---|---|
| 8–15 | Mild (OTC) | Light tiredness, minor swelling, everyday wear |
| 15–20 | Moderate (OTC) | Travel, on-feet jobs, pregnancy, sport, mild varicose veins |
| 20–30 | Firm (medical) | Pronounced varicose veins, moderate oedema, post-DVT — usually fitted |
| 30–40 | Extra firm (medical) | Severe oedema, lymphoedema, healed venous ulcers — prescription and fitting |
Getting the fit right
Compression is “graduated” — tightest at the ankle and easing up the leg — so it must be sized to your ankle and calf measurements, ideally taken first thing in the morning before swelling builds, not just your shoe size. A sock that rolls down or digs a tight band into the calf is the wrong size and can act like a tourniquet. Our compression socks guide covers measuring and putting them on.
Stop and seek advice if compression socks cause increasing pain, numbness, tingling, colour change in the toes, or skin breakdown — these can signal that the circulation needs assessing.
Frequently asked questions
- What compression level do I need for flights?
- For travel and clot prevention, 15-20 mmHg is the usual recommendation for people without diagnosed vein disease. Move your ankles regularly and stay hydrated too.
- Is 20-30 mmHg safe to buy without a doctor?
- It is sold over the counter in many places, but 20-30 mmHg is medical-grade. Because it is not suitable for everyone, it is best chosen with a doctor or pharmacist, especially if you have circulation problems.
- Can compression socks be harmful?
- Yes, if the level is too high for you or the fit is wrong. People with peripheral artery disease, some heart conditions, or skin infections should not use firm compression without medical clearance.
- How long should I wear them each day?
- Most daytime compression is worn when you are up and about and removed at night, unless a clinician advises otherwise. Follow the guidance that comes with a prescribed pair.