EU to UK Sock Size Chart 2026
Converting an EU sock size to a UK shoe size is simple once you stop treating it as guesswork and start treating it as a foot-length lookup problem — here's exactly how to do it in under two minutes.
- EU to UK sock size conversion runs on foot length in cm, not shoe brand — EU 42 sits at UK 8, EU 39 sits at UK 5.5-6.
- Wool-blend socks like Nordic Sock Company's Ultra Warm Finnish Wool Socks stretch to cover 2-3 UK sizes, so exact conversion matters less than fit-range.
- Measure heel-to-toe in cm first, then match to the EU-UK chart — reading the label alone gets it wrong roughly a third of the time.
- Half sizes (EU 39, EU 41) split across two UK sizes — always round to the snugger fit for wool socks worn in boots.
Why this matters
UK shoe sizing and EU sizing don't share a scale — UK counts in imperial barleycorns, EU counts in Paris points (roughly two-thirds of a centimetre). That gap is why an EU 40 sock can feel loose on one UK 6 foot and snug on another.
Get the Nordic Sock Company size wrong and a wool-blend sock either bunches at the toe or slips down inside a wellington boot by lunchtime. Neither is comfortable through a British winter, and in 2026 most Nordic-style sock brands still print EU sizing only, so the conversion step isn't optional if you shop from Scandinavia or Europe.
What you'll need
- A tape measure or ruler (cm markings, not just inches)
- A sheet of paper and a pen, or a wall to stand against
- The EU size printed on the sock label or product page
- A EU-UK conversion chart (below covers adult sizes)
- 5 minutes, barefoot or in a thin liner sock
If you're sizing up a specific pair — say, the Ultra Warm Finnish Wool Socks — check whether the listing gives a size range (e.g. EU 39-42) rather than a single number. Wool-blend socks are knitted with give, so most Nordic-style ranges cover two or three UK sizes per size band.
The steps
1. Measure your foot length in centimetres
Stand on a piece of paper with your full weight on your foot, heel against a wall. Mark the tip of your longest toe and measure heel to mark in cm. This number is more reliable than any shoe you own, because shoe sizing varies by last shape and brand, but foot length in cm doesn't.
2. Find the EU size on the label or listing
EU sizes are usually printed as a single number (40) or a range (39-42) on wool and Nordic-style sock packaging. Note it down exactly as written — don't round it in your head yet.
3. Cross-reference against the EU-UK chart
Here's the standard adult conversion:
| EU size | UK size | Foot length (cm) |
|---|---|---|
| 36 | 3 | 22.5 |
| 37 | 4 | 23.5 |
| 38 | 5 | 24.1 |
| 39 | 5.5-6 | 24.8 |
| 40 | 6.5-7 | 25.4 |
| 41 | 7.5 | 26 |
| 42 | 8 | 26.7 |
| 43 | 9 | 27.3 |
| 44 | 9.5-10 | 27.9 |
| 45 | 10.5-11 | 28.6 |
| 46 | 11.5-12 | 29.4 |
Match your cm measurement from step 1 to this table first, then use the EU size on the label as a cross-check — the two should land within one row of each other.
4. Round toward the snugger UK size for wool
When your foot length sits between two rows, round down for wool-blend socks. Wool has natural give and will stretch slightly with wear, but it won't shrink to fit a foot that's genuinely too big for the size — going snug beats going loose here.
5. Check the EU range, not just the midpoint
A sock listed EU 39-42 is built to stretch across UK 5.5 through UK 8. If your cm measurement puts you at the very top of that range (UK 8), the sock will still fit, but it'll sit at the looser end of that pair's stretch — worth knowing before you commit to a colour you can't return easily.
6. Confirm against your usual boot size, not your trainer size
Boot sizing and trainer sizing for the same UK number often differ by half a size because of insole thickness. If you wear the socks with wellingtons or hiking boots, size the sock to the boot, not the trainer — this is a common mismatch when measuring your foot properly is skipped and people convert from memory instead.
7. Try the sock on before cutting any tags
Wool-blend socks like the Norwegian Fjord Socks settle differently once worn in — give them a short walk around the house with tags intact so a straightforward exchange is still possible if the conversion lands you between sizes.
Common mistake: converting from a shoe size printed on a box rather than measuring the actual foot. Shoe sizing drifts by manufacturer; a cm measurement doesn't.
Troubleshooting
The sock size matches the chart but still feels tight across the toes. Wool-blend yarn is denser than cotton and takes a day or two to relax with wear — give it one full wear before deciding the size is wrong.
My foot measures between two UK sizes. Round to the snugger UK size for wool socks worn daily, and the looser UK size if the socks are mainly for lounging or bed.
The sock shrank slightly after the first wash and now feels off. This is a washing issue, not a sizing issue — wool tightens in hot water or a tumble dryer, and it doesn't fully reverse.
Kids' sizing chart doesn't match this table. Children's EU-UK conversion runs on a different scale entirely (EU 30 sits around UK 11.5 child's), so don't apply the adult chart above to a child's foot.
The listing only gives an EU range, no single number. Measure in cm and match the range's midpoint — a range like EU 39-42 is built to stretch, so exact precision matters less than for a rigid shoe.
Heel doesn't line up inside the boot. This is almost always a boot-fit issue rather than a sock-size issue — check the boot's own sizing first before re-measuring the sock.
Tools and resources
- A cm-marked tape measure or ruler
- The EU-UK chart above, printed or bookmarked
- Guidance on choosing the right sock thickness for winter once size is sorted
- Your usual winter boots, for a real-world fit check
- 2026 sizing note: most Nordic-style wool sock ranges still list EU only, so this chart is the fastest route to a UK match without ordering two sizes to compare
What to do next
Once the size is confirmed, the next variable that affects comfort is thickness rather than length — a sock sized correctly in EU-UK terms can still feel wrong if it's too thin for the boot it's going in, or too thick for a snug trainer. Sort thickness after size, not before, and the fit issue usually disappears.
FAQ
What is EU 40 in UK sock sizes?
EU 40 converts to roughly UK 6.5-7, matching a foot length of about 25.4cm. Round down to UK 6.5 for a snugger fit in wool-blend socks.
Is EU to UK sock sizing the same as shoe sizing?
Yes, sock sizing follows the same EU-UK scale as shoes because socks are sized to fit inside a specific shoe range. The only difference is socks often list a range (e.g. EU 39-42) rather than one number, since wool stretches.
How do I convert EU sock size to UK without a chart?
Measure foot length in cm and subtract roughly 1.5cm per EU size step down to reach the UK equivalent, though using a printed chart avoids rounding errors. A UK 8 foot measures about 26.7cm, for reference.
Do wool socks run big or small compared to the EU size on the label?
Wool-blend socks generally run true to the printed EU range and stretch slightly with wear, rather than running small. If anything, size down within a listed range rather than up.
What UK size is EU 42 in socks?
EU 42 is UK 8, at a foot length of about 26.7cm. This is one of the most common adult male sizes in Nordic-style wool sock ranges.
Why do some socks list EU 39-42 instead of a single size?
Wool-blend yarn stretches enough to comfortably fit a 3-4 UK size range from one knit size, which is why many 2026 Nordic sock ranges use bands rather than exact sizes. Check the cm measurement if you're at either end of the range.
Is UK sock sizing different for men's and women's socks?
The UK numbering scale is the same for men's and women's feet, but women's socks are typically knitted for the EU 36-41 range and men's for EU 40-46. Check the specific product's range rather than assuming by gender label.
How much does foot length change the sock size I need?
Every full UK size step corresponds to roughly 0.7cm of foot length, so a measurement error of even 1cm can push you a full size out. This is why measuring barefoot on paper beats guessing from a shoe box.
One last thing
The range-based sizing on wool-blend socks (EU 39-42, EU 43-46) isn't a shortcut manufacturers take — it's a function of the yarn. A tightly knitted wool-blend sock genuinely does stretch further than a cotton sock of the same knit size, which is why a single Nordic Sock Company size often covers three UK shoe sizes without the fit feeling compromised at either end.