What Does 8-15 mmHg Mean in Compression Socks? | Light Support Guide

That number on the sock package can look clinical, but it is actually a simple pressure reading. When a compression sock says 8-15 mmHg, it means the sock applies a light, measured squeeze to your lower leg — the gentlest tier on the compression scale and the one most people meet first.

What mmHg Measures in Compression Socks

mmHg stands for millimeters of mercury, the same pressure unit used in blood pressure cuffs. In compression socks, the number tells you how much force the fabric applies to your leg. Higher numbers mean stronger compression.

• 8-15 mmHg — light/mild compression for everyday comfort
• 15-20 mmHg — moderate support, often used for mild varicose veins and travel
• 20-30 mmHg — firm medical-grade compression for more significant vein issues
• 30-40 mmHg — the strongest tier, usually prescribed for serious conditions

Sources differ slightly on where one category ends and the next begins, but they consistently place 8-15 mmHg at the lowest tier. Cleveland Clinic’s guidance on compression socks describes this range as light support that simply feels like a firm hug around the leg — never a painful squeeze.

Who 8-15 mmHg Is Actually For

This level targets mild symptoms and prevention, not treatment of serious circulation problems. You reach for 8-15 mmHg when your legs feel tired and heavy at the end of a long day on your feet, or when you want light support during a long flight or road trip.

Common uses include:

• Tired, aching legs from prolonged sitting or standing
• Very minor swelling, especially around the ankles
• Light everyday support during travel or long workdays
• Early pregnancy leg discomfort, if cleared by a clinician

If you are trying to decide which level fits your situation, guidance on choosing properly can help — our top-rated 8-15 mmHg compression socks roundup covers tested pairs for everyday use.

How to Measure and Wear Them Properly

The right fit matters more than the brand. Compression socks work by squeezing from the ankle upward, which helps push blood back toward the heart. If the socks are too loose, they do nothing. If too tight, they can cause problems instead of preventing them.

Measure your legs in the morning before swelling sets in, using a tape measure at the ankle, calf, and along the length specified on the manufacturer’s sizing chart. Never rely on shoe size alone — calf circumference, in particular, varies a lot between people.

When you put them on, the socks should feel snug at the ankle with a gradually lighter grip toward the knee. They should never leave deep red marks, cause numbness, or make your toes feel cold. If you experience pain, tingling, discoloration, or worsening swelling, remove the socks and seek medical guidance.

Who Should Avoid Compression Socks

Light compression is a comfort tool, not a medical treatment — and when in doubt, a doctor’s opinion beats any package label.