To measure for compression socks, you need a soft measuring tape, bare legs, and about two minutes. The specific measurements depend on the style you’re buying, but most people shopping for knee-high compression socks need just two numbers: your calf circumference at its widest point and the length from your heel to the bend of your knee. Getting these right is the difference between socks that work comfortably and ones that slide down, pinch, or fail to provide proper pressure.
When and How to Set Up
Take your measurements first thing in the morning, right after getting out of bed. Your legs swell throughout the day from gravity and activity, and measuring later can give you inflated numbers that lead to socks that are too loose when you actually put them on. Compression socks are meant to prevent swelling, so you want your baseline, non-swollen leg size.
Use a soft, flexible measuring tape (the kind used for sewing, not a metal retractable one). Measure on bare skin, not over pants or leggings. Stand upright with your feet flat on the floor and your weight distributed evenly on both legs. If you have trouble reaching down or reading the tape, ask someone to help. Measure both legs, since they can differ in size, and use the larger measurement if you’re buying a single pair.
Knee-High Compression Socks
Knee-high is the most common style, and it requires two measurements:
- Calf circumference: Wrap the tape around the widest part of your calf. This is typically the thickest, fleshiest area roughly halfway between your knee and ankle. Pull the tape snug but not tight. You should be able to slide a finger underneath.
- Leg length: Measure from the back of your heel (where it meets the floor) straight up to the bend behind your knee. You can find this spot by bending your knee slightly. The crease that forms is where a knee-high sock should stop.
Some brands also ask for your ankle circumference. If so, measure around the narrowest point of your ankle, just above the bony bumps on either side. This is usually a couple of inches above where your foot meets your leg.
Thigh-High and Waist-High Styles
If you’re measuring for thigh-high stockings, you’ll need everything listed above plus two additional measurements:
- Thigh circumference: Measure around the widest part of your upper thigh, typically just below your buttock crease.
- Leg length (full): Measure from the floor (or back of the heel) up to the point on your upper thigh where the stocking will end. For thigh-highs, this is usually just below the gluteal fold.
Waist-high (pantyhose-style) compression stockings add a hip and waist circumference measurement. Wrap the tape around the widest part of your hips and then around your natural waist, which sits above your hip bones and below your rib cage.
Reading a Size Chart
Once you have your numbers, compare them to the brand’s size chart. Every manufacturer uses slightly different ranges, so a “medium” from one company may not match a “medium” from another. Always check the chart for the specific brand you’re buying rather than going by a size you’ve worn before.
Your calf circumference is typically the primary measurement that determines your size. If your calf falls clearly within one size range, that’s your size. When your measurements land between two sizes, the general rule is to size down for a snugger fit (which maintains better compression) rather than sizing up. However, if your leg length is long relative to your calf size, or if you’re between sizes on multiple measurements, some brands offer wide-calf or tall options that may fit better than simply going up a size.
What Happens With the Wrong Size
Compression socks that are too large won’t apply enough pressure and tend to bunch or slide down, which defeats their purpose entirely. Socks that are too small create problems in the other direction: they can dig into your skin, restrict blood flow at the top band, or cause discomfort that makes you not want to wear them.
Properly fitted compression socks should feel snug, especially around the ankle, with pressure that gradually decreases as the sock moves up your leg. They should never cause pain, numbness, or color changes in your toes or feet. Tingling, a deep crease mark at the top of the sock, or skin that turns white, blue, or purple are all signs the fit is wrong. If any of those happen, take the socks off and reassess your sizing.
Tips for Tricky Situations
If you have active swelling from a condition like lymphedema or chronic venous insufficiency, the standard “measure in the morning” advice still applies, but your healthcare provider may want to reduce the swelling first with bandaging before you’re fitted. Measuring over a swollen leg can result in socks that become too loose once swelling goes down with treatment.
If your calves are muscular or asymmetrical, measure both legs separately. Some people find that their left and right legs differ by a full size. In that case, you may need to buy two individual socks rather than a pair, which some medical supply companies offer. For people with unusually wide calves or very slim ankles, custom-fitted compression stockings are available through medical supply stores and typically require a fitting appointment with a trained specialist.