Introduction
In 2026, the secret to DVT prevention and leg comfort on long trips is well known: compression socks. They are your #1 defense against “Economy Class Syndrome.” But when you begin shopping for them—whether online or at a specialty store—the first thing you will notice is a strange number label: 15-20 mmHg, 20-30 mmHg, or 30-40 mmHg.
What does this “mmHg” mean, and which level is right for you? At VaricoseMD, we break down the clinical definitions so you can shop with confidence.
What is mmHg? (The “Millimeters of Mercury”)
The abbreviation “mmHg” stands for Millimeters of Mercury—the standardized unit of measurement for pressure. In the context of compression stockings, it measures the “squeeze” the fabric places on your limb. All medical-grade socks must offer graduated compression, meaning the pressure is highest at the ankle and gradually decreases up the leg.
The 3 Levels of Travel Compression
Level 1: 15-20 mmHg (Mild to Moderate)
This is the “starter” level. It is the perfect balance of effective pressure and daily comfort.
- Best For: Preventive travel (flights or road trips under 4 hours), managing mild, occupational “heaviness,” and people with healthy veins who simply want to prevent fluid retention.
- The Result: Legs that feel lighter and less tired at the end of a trip.
Level 2: 20-30 mmHg (Moderate to Firm)
This is the standard medical grade. It is often the minimum requirement for insurance providers.
- Best For: High-risk travel (long-haul flights over 4 hours), patients with diagnosed venous insufficiency or visible varicose veins, and post-procedure recovery (like after VenaSeal).
- Note: You may need a prescription from your doctor to ensure this level is appropriate and to get proper measuring.
Level 3: 30-40 mmHg (Firm to Extra Firm)
This is the most potent medical grade. A prescription is mandatory.
- Best For: Severe venous insufficiency, managing active venous ulcers, or patients with a confirmed history of DVT (blood clots). This level is rarely used solely for “travel” but rather for managing chronic conditions.
Conclusion
When it comes to compression socks, “more” is not always better. For most travelers, the 15-20 mmHg is the sweet spot. Choosing the right pressure prevents DVT and ensures your trip is as comfortable as your destination. If you are unsure, always consult a pro.
Struggling to find the right fit? Many vein clinics in our directory offer professional measuring services to ensure you get the perfect sock for your specific anatomy. Browse the VaricoseMD Directory to find a clinic that fits your needs.
