The Complete Guide to the Shoe Size Converter
Buying shoes from an international retailer or browsing a foreign brand's store can be confusing because every region labels sizes differently. Korea and Japan print the foot length directly in millimeters (mm), the United States uses US sizing, the United Kingdom uses UK sizing, and continental Europe uses EU sizing. On top of that, men's and women's number systems are not the same, so an accurate conversion really matters. With this converter you can turn a foot length in millimeters into US, UK and EU sizes in a single click, helping you avoid the all-too-common mistake of ordering the wrong size from abroad.
Understanding Each Country's Shoe Size System
Korea & Japan (mm) — the foot-length system
Korea and Japan measure shoes by the actual foot length in millimeters. For example, 270 mm suits a person whose foot is about 27 cm long. This is the most intuitive system because the number almost exactly matches real foot length. Men typically fall in the 250–290 mm range, while women are commonly 220–260 mm. Japanese brands such as Asics and Mizuno also use this cm/mm labeling, so the Korea-Japan column applies to both markets.
United States (US) sizing
US sizing uses different numbers for men and women. The same physical foot will carry a different number depending on gender, so be careful: for an identical foot length a women's US size is roughly 1.5 higher than the men's number. Most American brands, including Nike, New Balance and Converse, follow this system.
United Kingdom (UK) sizing
UK sizing looks similar to US sizing but the numbers are offset. For men, a UK size is usually about 0.5–1 lower than the equivalent US size. When shopping British brands such as Dr. Martens, Clarks and Reebok, refer to the UK column.
Europe (EU) sizing
EU sizing is unisex — men and women share the same number system. It is based on the Paris Point system and produces relatively large numbers (roughly 36–48). Use the EU column for European brands like Adidas, Puma, Zara and H&M.
What to Watch For When Buying Shoes Internationally
Sizing differs by brand
Even at the same US number, the real fit varies between brands. Nike tends to run narrow, while New Balance is more generous. Adidas has a relatively low instep, and the Converse Chuck Taylor is widely known to run about half a size large. If you are buying a brand for the first time, always read its fit reviews before ordering.
Consider foot width
Many people have wider feet than the average European last is designed for. For narrow-cut European brands, ordering half a size up (about 5 mm) can be the safer choice. On the other hand, brands that offer dedicated wide options — such as New Balance and Asics — can be ordered in your true size.
Fit differences by shoe type
- Running shoes: leave about 1 cm of room in front of the toes, since your foot slides forward as you run.
- Casual sneakers: true to size or half a size up is typical.
- Dress shoes: true to size or half a size down, because leather stretches with wear.
- Hiking boots: half a size to a full size up to allow for thick socks.
- Slides / sandals: usually true to size, but it varies by brand.
How to Measure Your Foot Length Accurately
To find the right shoe size you first need to measure your foot length correctly. Follow these steps.
- Place a sheet of A4 paper on a flat, hard floor and stand on it.
- Put your heel against a wall and stand naturally with your weight on the foot.
- Mark the tip of your longest toe with a pen.
- Measure the distance from the wall (heel) to the mark with a ruler.
- Measure both feet and use the larger one to choose your size.
- Measure in the afternoon — feet swell slightly over the course of the day.
Conversion Tips and Quick Reference
When an exact size is unavailable, rounding up to the next half size is usually safer than going down, because a roomy shoe can be tightened with insoles or thicker socks. Keep in mind that the men's and women's tables below are separate: a 250 mm foot maps to US 7 for men but US 8 for women. EU numbers are unisex, so the EU column is the easiest common reference point when you are unsure which gender chart a listing uses. If a product page only shows a single regional number, convert it back to millimeters here first and then read across to the system you need.
Frequently Asked Questions (FAQ)
Q. What US size is a 270 mm foot length?
A. For men, 270 mm corresponds to US 9; for women it corresponds to US 10. Brands vary slightly, so it is best to also check the size chart for the specific brand you are buying.
Q. Do Nike and Adidas use the same size?
A. At the same US number, the fit of Nike and Adidas can differ. Nike runs relatively narrow with a low instep; Adidas also has a low instep but is sometimes a touch roomier in the toe box. In general, both brands use the same US size for a given foot length in millimeters.
Q. What if there is no half size?
A. When your exact size is not offered, choosing the half size up (the larger option) is usually the safe bet. A slightly large shoe can be adjusted with insoles or thicker socks, while a too-small shoe cannot.
Q. Are EU sizes the same for men and women?
A. Yes, EU (European) sizes are unisex. The same foot length maps to the same EU number for both men and women. The shoes themselves may still differ in width and design.
Q. How do US, UK and EU sizes relate to each other?
A. For the same foot, a men's US size is roughly half a size to a full size higher than the UK number, while EU numbers run much higher (in the 36–48 range) because they use a different unit entirely. Use the millimeter column as your anchor and read across to compare any two systems reliably.
Q. Can I convert children's shoe sizes?
A. This converter provides adult (men's / women's) conversions. Children's shoes use a separate size system that differs significantly by brand, so we recommend checking the relevant brand's children's size chart directly.