Core answer: Foot length 25.0 cm = China size 250 = EU 40 = US men's 7.5 / women's 9 = UK 6.5. The conversion trick: reduce everything to foot length in centimeters first, then look it up. When shopping online, always go by foot length — never trust "I usually wear size X".
How the four sizing systems map
| System | Definition | Conversion from foot length (cm) |
|---|---|---|
| China (CN) | Foot length in millimeters | CN = foot length × 10 |
| EU | Paris point (2/3 cm) | EU ≈ foot length × 1.5 + 10 |
| US | Inch-based; men's and women's run on different tracks | Men ≈ EU − 31.5; women ≈ EU − 29 |
| UK | ~0.5–1 below US | Men ≈ US − 0.5 to 1 |
The EU formula is approximate; last shapes vary ±0.5 size by brand.
Men's conversion table
| Foot length (cm) | CN | EU | US | UK |
|---|---|---|---|---|
| 24.5 | 245 | 39 | 6.5 | 6 |
| 25.0 | 250 | 40 | 7.5 | 6.5 |
| 25.5 | 255 | 41 | 8 | 7.5 |
| 26.0 | 260 | 42 | 9 | 8 |
| 26.5 | 265 | 43 | 9.5 | 9 |
| 27.0 | 270 | 44 | 10.5 | 10 |
| 28.0 | 280 | 46 | 12 | 11 |
Women's conversion table
| Foot length (cm) | CN | EU | US | UK |
|---|---|---|---|---|
| 22.5 | 225 | 35 | 5 | 3.5 |
| 23.0 | 230 | 36 | 6 | 4 |
| 23.5 | 235 | 37 | 6.5 | 4.5 |
| 24.0 | 240 | 38 | 7.5 | 5.5 |
| 24.5 | 245 | 39 | 8.5 | 6 |
| 25.0 | 250 | 40 | 9 | 6.5 |
Kids' conversion table
| Foot length (cm) | CN | EU | US |
|---|---|---|---|
| 13.0 | 130 | 21 | 5C |
| 15.0 | 150 | 24 | 8C |
| 17.0 | 170 | 28 | 11C |
| 19.0 | 190 | 31 | 13C |
| 21.0 | 210 | 33 | 2Y |
Kids' shoes need 1 cm of growing room at the toes; re-measure every 3 months.
Measuring your foot in 4 steps
- Measure in the afternoon: feet swell slightly by then — closest to in-shoe state
- Stand on paper against a wall, heel touching it, mark the longest toe
- Measure wall-to-mark distance in millimeters — that is foot length
- Measure both feet and use the larger one
Five rules for buying shoes online
- Sneakers: foot length + 0.5–1 cm; basketball/hiking shoes add another half size
- Dress shoes: + 0.5 cm; narrow Italian lasts go up a full size
- High instep or wide feet: half size up, or pick wide lasts (2E/4E)
- Read the listing's insole length, not the size label: insole − foot length = 0.8–1.5 cm is the right fit
- Cross-border shopping: US men's and women's sizes run on separate tracks — US 7 men ≠ US 7 women (1.5 apart)
Common mistakes and myths
- "I always wear 40" — the same labeled size can differ by 1 cm of insole length across brands and categories (sneakers/leather/boots). Trust the listing's millimeter insole length.
- "25 cm foot = buy size 250 shoes" — CN 250 means *fits* a 250 mm foot; the insole is usually 255–260 mm. Shop by insole length.
- "Buy kids' shoes two sizes big" — over 1.5 cm of room harms gait development and raises flat-foot risk; one size up is the ceiling.
- "US and UK are about the same" — same number, ~1 size apart: US 9 ≈ UK 8. Mixing them guarantees a wrong buy.
Use the [Shoe Size Converter](/c/convert/shoe-size) to get all four size tracks from foot length or any size, and the [Clothing Size Calculator](/c/convert/clothing-size) for the rest of your cross-border haul.