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Convert between US, UK, EU, Japanese, Korean, and Brannock sizing systems with accurate conversion tables and measurement formulas.
6+ Systems
Worldwide
1 barleycorn
= ⅓ inch
~65%
Wear wrong size
268 mm
US Men's 10
Free online shoe size converter — convert between US, UK, EU, CM, and Inches instantly with AI-powered insights.
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Shoe sizing varies dramatically worldwide because different countries developed their systems independently over centuries. The major sizing systems — US, UK, EU (Continental), Japanese (Mondopoint), and Korean — each use different units, starting points, and increments, making direct comparison confusing without conversion charts.
The Brannock Device, invented by Charles Brannock in 1927 and still used in shoe stores today, measures foot length, width, and arch length. US and UK sizes are based on the barleycorn system (each full size = ⅓ inch = 8.47 mm). EU sizes use the Paris Point system (each size = ⅔ cm = 6.67 mm). Japanese and Korean systems use Mondopoint — centimeters or millimeters of foot length.
Studies show that approximately 65% of people wear shoes that don't properly fit, and poorly fitting shoes contribute to bunions, hammertoes, plantar fasciitis, and other foot problems. Proper measurement — ideally in the afternoon when feet are at their largest — and understanding how sizes translate across systems is essential for comfort and foot health.
US Men's Size: Size = (foot_length_in × 3) − 22 Size = (foot_length_cm × 3 / 2.54) − 22 US Women's Size: Size = US Men's + 1.5 (or: (foot_length_in × 3) − 20.5) UK Size: Size = US Men's − 0.5 (or: (foot_length_in × 3) − 22.5) Example: 10.5-inch foot US Men = (10.5 × 3) − 22 = 9.5 US Women = 9.5 + 1.5 = 11 UK = 9.5 − 0.5 = 9 Increment: 1 full size = ⅓ inch Half sizes = ⅙ inch (4.23 mm)
US and UK sizes differ by 0.5 for men's and 2.0 for women's. Children's sizes reset at ~size 13 before going to adult 1.
EU Size: Size = (foot_length_cm + 1.5) × 1.5 Size = (foot_length_cm × 1.5) + 2.0 Reverse (EU → cm): foot_cm = (EU_Size − 2.0) ÷ 1.5 Examples: 26.7 cm foot (US Men 10): EU = (26.7 + 1.5) × 1.5 = 42.3 → 42 EU 44 → cm: cm = (44 − 2.0) ÷ 1.5 = 28.0 cm Increment: 1 EU size = ⅔ cm = 6.67 mm No official half sizes exist, but some brands use them (e.g., 42.5) The +1.5 cm accounts for 'functional length' (toe room beyond foot length).
EU sizes are unisex — the same EU size applies to men and women. A women's EU 39 equals a men's EU 39.
Japanese (JPN) Size: Size = foot_length_cm (rounded to nearest 0.5 cm) Korean (KR) Size: Size = foot_length_mm (rounded to nearest 5 mm) Examples: 26.7 cm foot: JPN = 27.0 KR = 270 24.5 cm foot: JPN = 24.5 KR = 245 Mondopoint (ISO 9407): Notation: length/width in mm Example: 270/100 (270 mm long, 100 mm wide) Used by NATO military, ski boots, and increasingly by global brands.
| US Men | UK | EU | JPN (cm) | KR (mm) | Foot Length (in) | Foot Length (cm) |
|---|---|---|---|---|---|---|
| 6 | 5.5 | 39 | 24.0 | 240 | 9.25 | 23.5 |
| 6.5 | 6 | 39.5 | 24.5 | 245 | 9.5 | 24.1 |
| 7 | 6.5 | 40 | 25.0 | 250 |
| US Women | UK | EU | JPN (cm) | KR (mm) | Foot Length (in) | Foot Length (cm) |
|---|---|---|---|---|---|---|
| 5 | 2.5 | 35 | 22.0 | 220 | 8.5 | 21.6 |
| 5.5 | 3 | 35.5 | 22.5 | 225 | 8.625 | 21.9 |
| 6 | 3.5 | 36 | 23.0 | 230 |
| US Kids | UK Kids | EU | Age Range | Foot Length (in) | Foot Length (cm) |
|---|---|---|---|---|---|
| 1C | 0.5 | 16 | 0–3 mo | 3.5 | 8.9 |
| 3C | 2.5 | 18.5 | 3–12 mo | 4.25 | 10.8 |
| 5C | 4 | 20.5 | 12–18 mo | 4.875 | 12.4 |
| 7C | 6 |
| Width Code | Men's Description | Women's Description | Ball Width (Size 10) | Who It's For |
|---|---|---|---|---|
| AAA / 3A | Extra narrow | — | 3.25" | Very narrow feet, rare |
| AA / 2A | Narrow | Extra narrow | 3.5" | Narrow feet, slim builds |
| A | — | Narrow | 3.625" | — |
| B | Narrow | Standard | 3.75" | Men's narrow / Women's standard |
| C | — | Wide | 3.875" | — |
1324
King Edward II of England decrees the barleycorn system: 3 barleycorns = 1 inch, with shoe sizes based on foot length in barleycorn increments. This system persists in US and UK sizing today.
1800s
The Paris Point system emerges on continental Europe (⅔ cm increments), creating the EU sizing system. Shoes are made on wooden lasts, and sizing remains inconsistent between shoemakers.
1880s
Edwin B. Simpson publishes the first systematic shoe size chart in the US, attempting to standardize the chaotic sizing landscape. Left and right shoes (vs. straight lasts) become standard.
1927
Charles Brannock patents the Brannock Device, a mechanical foot-measuring instrument that measures length, width, and arch length simultaneously. It remains the industry standard nearly 100 years later.
1991
ISO 9407 establishes the Mondopoint system (foot length and width in mm) as the international standard. It is adopted for military footwear (NATO), ski boots, and some athletic brands, though consumer adoption remains limited.
Research shows 65% of adults wear shoes that are too narrow or too short. Ill-fitting shoes are a leading cause of bunions, hammertoes, and metatarsalgia. AOFAS recommends measuring feet annually and fitting shoes in the afternoon.
Learn More →The International Organization for Standardization's shoe sizing standard defines foot measurement methodology and the Mondopoint sizing system (length/width in mm). Adopted by NATO and ISO member countries for military and safety footwear.
Learn More →Founded in 1927, the Brannock Device measures length, width, and arch length. Research by the company shows that arch length (distance from heel to ball of foot) is often more important than overall length for proper fit.
Learn More →Peer-reviewed studies on foot morphology show significant variation across populations. Asian feet tend to be wider relative to length than European feet. Children's feet may differ by 2+ sizes between brands, highlighting the need for actual measurement over size number.
Learn More →MYTH
Your shoe size stays the same throughout your adult life.
FACT
Feet change over time. Aging, weight gain, pregnancy, and conditions like arthritis can increase foot length by 0.5–1 full size. It's recommended to measure your feet at least once a year, especially after age 40.
MYTH
A size 10 is the same across all shoe brands.
FACT
There is no universal enforcement of shoe sizes. A Nike size 10 may fit differently than an Adidas, New Balance, or Allen Edmonds size 10. Variation of ±0.5 sizes between brands is common. Always try on shoes or check brand-specific sizing charts.
MYTH
EU sizes are more accurate than US/UK sizes because they're metric.
FACT
EU sizes are based on the Paris Point (⅔ cm), not on actual metric foot measurement. They also include an assumed 1–1.5 cm addition for toe room, which isn't standardized across manufacturers. Mondopoint (actual cm/mm) is the true metric system.
MYTH
You should always buy shoes that fit snugly — they'll stretch.
Stand on a piece of paper with your heel against a wall. Mark the tip of your longest toe. Measure from the wall to the mark in inches or cm. Measure BOTH feet — use the larger measurement. Do this in the afternoon when feet are slightly swollen (as they will be when wearing shoes).
For men's shoes: UK = US − 0.5 (so US 10 = UK 9.5). For women's shoes: UK = US − 2 (so US 8 = UK 6). Some brands use slightly different offsets, so always check the brand's own conversion chart.
Use the formula: EU ≈ (US Men's + 33) or (US Women's + 31.5). For example: US Men's 10 = EU 43-44. US Women's 8 = EU 39-39.5. This is approximate — tables in this guide provide exact conversions.
Mondopoint (ISO 9407) defines shoe size by foot length and width in millimeters. A '270/100' means 270 mm long, 100 mm wide foot. It's used for military boots, ski boots, and by some global brands. Japanese sizes use cm and Korean sizes use mm — both are simplified Mondopoint variants.
Convert between US, UK, EU, Japanese, and Korean shoe sizes with precision conversion tables and measurement guides.
Try the Shoe Size Converter →Last updated:
Mondopoint is the most straightforward system — it's simply your foot length. JPN uses cm, KR uses mm, and ISO Mondopoint adds width.
Width Scale (Men's):
AAA (thinnest) → AA → A → B →
C → D (standard) → E → EE/2E →
EEE/3E → EEEE/4E (widest)
Width Scale (Women's):
AAAA → AAA → AA → A → B
(standard) → C → D → E → EE
Measurement (ball-of-foot circumference):
Men's D (standard), size 10:
~4.0 inches wide
~10.1 inches circumference
Each width letter = ~¼ inch change
D to EE: ball is ½ inch wider
D to B: ball is ½ inch narrower
EU widths (when offered):
Narrow, Standard, Wide
or numeric: 5, 6, 7, 8, 9, 10Only ~20% of shoes come in multiple widths. Men's D and Women's B are 'standard' — if your foot is wider or narrower, seek brands offering width options.
| 9.625 |
| 24.4 |
| 7.5 | 7 | 40.5 | 25.5 | 255 | 9.75 | 24.8 |
| 8 | 7.5 | 41 | 26.0 | 260 | 9.9375 | 25.4 |
| 8.5 | 8 | 42 | 26.5 | 265 | 10.125 | 25.7 |
| 9 | 8.5 | 42.5 | 27.0 | 270 | 10.25 | 26.0 |
| 9.5 | 9 | 43 | 27.5 | 275 | 10.4375 | 26.7 |
| 10 | 9.5 | 44 | 28.0 | 280 | 10.5625 | 27.0 |
| 10.5 | 10 | 44.5 | 28.5 | 285 | 10.75 | 27.3 |
| 11 | 10.5 | 45 | 29.0 | 290 | 10.9375 | 27.9 |
| 11.5 | 11 | 45.5 | 29.5 | 295 | 11.125 | 28.3 |
| 12 | 11.5 | 46 | 30.0 | 300 | 11.25 | 28.6 |
| 13 | 12.5 | 47 | 31.0 | 310 | 11.5625 | 29.4 |
Sizes are approximate. Fit varies by brand, shoe style, and last shape. Always measure both feet — most people have one foot slightly larger.
| 8.75 |
| 22.2 |
| 6.5 | 4 | 37 | 23.5 | 235 | 8.9375 | 22.9 |
| 7 | 4.5 | 37.5 | 24.0 | 240 | 9.125 | 23.2 |
| 7.5 | 5 | 38 | 24.5 | 245 | 9.25 | 23.5 |
| 8 | 5.5 | 38.5 | 25.0 | 250 | 9.375 | 23.8 |
| 8.5 | 6 | 39 | 25.5 | 255 | 9.5 | 24.1 |
| 9 | 6.5 | 40 | 26.0 | 260 | 9.6875 | 24.6 |
| 9.5 | 7 | 40.5 | 26.5 | 265 | 9.875 | 25.1 |
| 10 | 7.5 | 41 | 27.0 | 270 | 10 | 25.4 |
| 10.5 | 8 | 42 | 27.5 | 275 | 10.1875 | 25.9 |
| 11 | 8.5 | 42.5 | 28.0 | 280 | 10.3125 | 26.2 |
EU sizes are unisex. US Women's = US Men's + 1.5. UK Women's sizes may vary by brand — always refer to the manufacturer's chart.
| 23 |
| 18–24 mo |
| 5.5 |
| 14.0 |
| 8C | 7 | 25 | 2–3 yr | 5.75 | 14.6 |
| 10C | 9 | 27 | 3–4 yr | 6.5 | 16.5 |
| 12C | 11 | 30 | 5–6 yr | 7.125 | 18.1 |
| 13C | 12.5 | 31 | 6–7 yr | 7.5 | 19.1 |
| 1Y | 13 | 32.5 | 7–8 yr | 7.75 | 19.7 |
| 3Y | 2 | 34.5 | 9–10 yr | 8.5 | 21.6 |
| 5Y | 4 | 37 | 11–12 yr | 9.125 | 23.2 |
| 6Y | 5 | 38.5 | 12+ yr | 9.5 | 24.1 |
C = Child, Y = Youth. Children's feet grow ~1 full size every 3-4 months. Measure frequently and leave ½ inch (thumb width) of room in the toe.
| D | Standard | Extra wide | 4.0" | Men's standard / Women's wide |
| E | Wide | — | 4.25" | Slightly wide feet |
| EE / 2E | Extra wide | — | 4.5" | Wide feet, common for work boots |
| EEE / 3E | Ultra wide | — | 4.75" | Very wide, medical needs |
| EEEE / 4E | Widest | — | 5.0" | Maximum width available |
Width increases ~¼ inch (6 mm) per letter. Width also scales with length — a size 12 D is wider than a size 8 D. Brands like New Balance, Brooks, and ASICS offer the widest range of width options.
2010s–present
3D foot scanning technology enters retail stores, providing precise measurements in seconds. Online retailers develop AI-powered fit prediction using purchase/return data. Despite technology advances, approximately 65% of people still wear incorrectly sized shoes.
FACT
Leather shoes may stretch slightly in width (1–3 mm) but NOT in length. Synthetic materials barely stretch at all. You should have about ½ inch (thumb width) between your longest toe and the front of the shoe. If shoes hurt in the store, they'll hurt at home.
MYTH
Buying a half-size bigger is always better than one too tight.
FACT
Shoes that are too large cause heel slippage, blisters, and toe gripping (which leads to hammertoes). Width is usually the issue, not length. If a shoe feels tight across the ball of the foot, try a wider width rather than a longer size.
MYTH
Children's shoe sizes follow the same system as adult sizes.
FACT
US children's sizing starts at 0 for newborns and goes to 13C, then RESETS to 1Y (Youth) for bigger kids. Youth 1Y ≈ the same foot length as children's 13C but is NOT equivalent to adult 1. There's a confusing gap at the children-to-adult transition.
This is extremely common — about 60% of people have asymmetric feet. Buy for the LARGER foot and use an insole or heel pad in the shoe for the smaller foot. Some specialty retailers sell mismatched pairs. Never size down to fit the smaller foot.
Aim for ½ inch (12–13 mm) — roughly a thumb's width — between your longest toe and the front of the shoe. For running shoes, allow ¾ inch (19 mm) because feet swell during exercise and you need room for the foot to slide forward on downhills.
Leather stretches slightly in WIDTH (1–3 mm) over the first few weeks of wear. Length does NOT change. Synthetic materials, canvas, and mesh have minimal stretch. If shoes are uncomfortable in length, don't count on stretching — exchange for a different size.
US kids' sizes start at 0C (newborn). Toddler sizes run C1–C13. After 13C, sizes reset to 1Y (Youth), going up to 7Y. Youth 7Y ≈ Women's 8.5. There's no perfect overlap — measure the child's foot in cm and use the measurement charts above.
Asian sizing systems (Japanese/Korean) use the Mondopoint approach based on actual foot length. Asian populations also tend to have wider feet relative to length, so Western shoes may fit differently. Japanese brands like ASICS and Mizuno may run narrower in Western markets.
D is the standard (medium) width for men. B is the standard (medium) width for women. Letters below are narrower (C, A, AA, AAA for men), and letters above are wider (E, EE, EEE for men). Each letter represents approximately ¼ inch (6 mm) difference in width.
Not necessarily. Running shoes typically run ½ size larger than dress shoes for the same foot, and they're designed for a different last shape. Athletic shoes should be fitted with ¾ inch of toe room while standing, whereas dress shoes may be fitted closer. Measure for each type separately.
Most online converters are reasonably accurate for standard sizes (within ±0.5 sizes). However, they can't account for brand-specific variation, foot width, arch height, or the different lasts used for different shoe styles. Use converters as a starting point, then check brand-specific charts and reviews.