Socks Size Chart
| US Shoe Range | UK Shoe Range | EU Shoe Range |
|---|---|---|
| S (4-6) | 3-5 | 35-38 |
| M (7-9) | 6-8 | 39-42 |
| L (10-12) | 9-11 | 43-46 |
Sizing conventions vary by brand and cut. See how this chart is compiled.
Socks are sized by a shoe-size range, not a foot measurement
Unlike almost every other garment on this site, a sock size isn't derived from a direct body measurement at all — it's labelled by the range of shoe sizes it's meant to stretch across, which is why a sock package reads something like "9-11" rather than a single number. Converting a sock size across US, UK, and EU therefore means converting shoe-size ranges, not measuring feet.
That range logic is exactly why one sock size fits several shoe sizes
A knit sock relies on its own elasticity to close the gap between the low and high end of its labelled range, which is why the same S/M/L sock band can honestly claim to fit a multi-size spread of feet — the stretch of the fabric, not a precise measurement, is doing the actual size-adaptation work once you're inside the labelled range.
Converting the range means converting both endpoints
Because a US sock range like 9-11 maps to a UK shoe range and a separate EU shoe range, an accurate conversion has to translate both the low and high end of the printed range using standard shoe-size conversion, rather than converting a single midpoint number — the individual shoe conversion charts on this site are the more precise reference if you know your exact shoe size in one system already.
Compression and athletic socks size by calf circumference instead
Graduated compression socks and many athletic performance socks abandon the shoe-size-range convention entirely and size by calf circumference and sometimes height, since their fit purpose (controlled pressure at the calf, arch support in a specific zone) depends on a different part of the leg than a standard crew or ankle sock does — checking the specific brand's calf-circumference chart matters more than the shoe-range printed on a standard sock.
Dress socks and thick winter socks tolerate the range differently
A thin dress sock, sized to disappear inside a dress shoe, has less spare material to stretch across its printed range than a thick wool hiking or winter sock does — if you're at the extreme edge of a printed range (the very smallest or very largest foot within it), a thinner dress sock is more likely to feel loose at the heel or tight across the instep than a thicker sock covering the same nominal range.
Kids' sock sizing follows shoe-size ranges too, but changes fast
Children's sock ranges track children's shoe-size ranges the same way adult socks do, but because kids' feet grow through several shoe sizes in a single year, a sock bought at the bottom of its labelled range is worth buying generously rather than exactly, since it will likely need to stretch to cover growth well before it wears out.
When in doubt, match to your shoe size, not a foot-length ruler
The fastest way to buy the right sock abroad is to convert your known shoe size into that country's shoe-size system first (using the shoe charts elsewhere on this site), then find which printed sock range that converted shoe size falls inside — trying to measure sock size directly off a foot-length ruler skips the step the label is actually built around.
No-show and low-cut socks add a second, unlabelled fit variable
Beyond the printed shoe-size range, a no-show or low-cut sock has to also clear the heel of a specific shoe without slipping down inside it, which is a function of the sock's heel-tab design and grip silicone as much as its labelled size — two socks in the identical printed range can behave very differently once actually worn inside a low-cut shoe, something no size chart captures.
Toe socks and five-finger sock designs size by foot width as well as length
A toe sock, built with individual finger-like pockets for each toe, needs the width across the forefoot to be right in addition to the overall shoe-range fit — a pocket built too narrow for a wider forefoot will bind between the toes regardless of whether the shoe-size range on the package is otherwise correct. A standard sock has no such failure mode; a toe sock does, so check width specifically before buying one.
Wool and natural-fibre socks shrink differently than synthetic blends
A wool or wool-blend sock can genuinely shrink after a first wash if not cared for according to the label, tightening its effective range downward from what the size printed at purchase suggested, while a synthetic or synthetic-blend sock generally holds its dimensions far more consistently wash after wash — factor this into sizing choices for a wool sock bought near the small end of its labelled range.
European sock ranges are printed against EU shoe sizes, not a separate scale
A European sock package's printed range (say, 39-42) is simply the EU shoe-size range translated directly, with no independent European sock-numbering convention to learn on top of it — anyone who already knows their EU shoe size can read a European sock range at face value without a further conversion step.
Toddler socks add a stay-on mechanism that adult sizing doesn't need
Toddler and infant socks frequently include a ribbed cuff or grip band specifically engineered to stop the sock working itself off a foot that hasn't yet developed the ankle definition an adult foot has, meaning the printed shoe-size range on a toddler sock matters slightly less than whether that stay-on mechanism actually holds for a particular child's ankle shape.
Anti-blister and hiking socks add a padding-zone consideration to fit
A hiking or anti-blister sock often builds in extra cushioning at the heel and forefoot specifically, which takes up a bit more internal volume inside a shoe than a standard thin sock does at the same printed shoe-size range, worth remembering when pairing a thicker hiking sock with boots sized precisely to bare-foot measurements.
Frequently asked questions
What's the fastest way to buy the right sock size internationally?
Convert your known shoe size into the target country's shoe-size system first, then check which printed sock range that converted size falls within — and if the converted size lands right on the boundary between two printed ranges, several brands sell a combined dual-range pack (for example, a single package spanning both a "6-8" and a "9-11" range) specifically for this situation, which sidesteps picking between the two entirely.
Can I just measure my foot length directly to pick a sock size?
It's less reliable than converting your shoe size, since sock labels are built around shoe-size ranges rather than a direct foot-length measurement — if you've already worn a specific brand's socks comfortably before, noting that brand's exact printed range on the packaging you kept is a faster and more accurate reference for a repeat order than either measuring or converting from scratch.
Why do my no-show socks slip inside my shoe even though the size is right?
Check the shoe's own interior lining before blaming the sock — a smooth leather or synthetic lining gives the sock's grip silicone almost nothing to bite into, while a textured fabric lining holds a no-show sock in place far better at the identical size and brand, so the same 'right size' sock can behave completely differently depending on what it's paired with.
Will my wool socks still fit their labelled range after washing?
It depends heavily on the wool percentage on the label, not just the fibre type — a sock blended with a meaningful share of nylon or synthetic reinforcement shrinks far less than a high-percentage or 100% wool sock, so checking the exact composition line, not just whether 'wool' appears on the label at all, predicts how much a specific pair will actually tighten.
Do hiking socks need extra shoe-fit consideration beyond the printed range?
Yes — their added heel and forefoot cushioning takes up more internal shoe volume than a standard sock, worth accounting for when pairing with boots sized close to bare-foot measurements.
Are diabetic or medical-comfort socks sized the same shoe-range way as standard socks?
The range convention is usually similar, but the priority differs — diabetic socks are built seamless and non-binding specifically to avoid pressure points on sensitive feet, so a correctly ranged pair can still feel different than a standard sock, and checking a specific medical-sock brand's own fit notes matters more here than for ordinary socks.
Does the fiber (wool, cotton, or synthetic) change how a sock's printed range fits on day one, separate from washing?
Yes — a wool sock generally has more natural give across a printed range than a tightly-woven cotton sock does, while a synthetic blend sits somewhere between the two, so two socks in the identical printed range but different fibers can feel meaningfully different in a shoe before either one has ever been washed.
Do socks sold as a single pair need a different size check than a multi-pack of the same range?
Not usually — a single pair and a multi-pack from the same brand typically share identical range sizing, so there's no separate conversion step; the more relevant difference is usually price per pair rather than fit.
If I'm exactly between two shoe sizes that straddle a sock range's printed boundary, which range should I buy?
Buy the range that includes your larger shoe size — a sock's stretch handles the smaller end of a range far more forgivingly than it compensates for being genuinely one size too small at the top end, so when in doubt, sizing toward the higher range is the safer default. This matters most right at a printed range boundary — well within the middle of a range, either direction settles comfortably.