Shoe Size Converter
US, UK, EU, JP shoe sizes from foot cm.
What it does
Shoe sizes translate through foot length, not each other. A 27 cm foot reads JP 27 by Mondopoint definition, about US 10 by inch math, UK 9 by offset, and EU 42.5 by Paris points. Length anchors every system; history scrambles the rest.
The tool above converts foot centimeters to four systems. Enter length and it prints US (nearest half), UK with EU, and JP with millimeters. Defaults show the 27 cm foot; 25 cm reads US 7.5 with UK 6.5 and EU 39.5.
Standards bodies frame the honesty. ISO 9407 defines Mondopoint sizing with JIS aligned to it, while ISO 19407 publishes conversion tables as guidelines because systems grew separately with no exact solution. Sample rows place 270 mm near EU 42.5 and UK 9.
Lasts defeat charts at the margins. Toe boxes, widths, socks, and brands shift fit by half to full sizes around any conversion, so measure both feet standing and try on the larger. Maker charts beat universal math for final buys.
How to use
- Measure the longer foot in cm, standing.
- Enter the centimeters.
- Read US first, then UK and EU.
- Read JP/Mondopoint beside it.
- Fit the larger foot.
- Check maker charts before buying.
Formula
- foot cm
- Longer foot length in cm, 15 to 35.
ISO 9407 Mondopoint base with JIS alignment; ISO 19407 states conversions are guidelines, not exact.
Worked example
Example: 27 cm foot
Defaults: 27 cm foot.
- Input: 27 cm foot length.
- JP: 27 cm reads JP 27 (Mondopoint).
- US: 3 x 10.63 minus 22 = 9.89, about US 10.
- UK: US minus 1 = UK 9. EU: (270+13.5)/6.67 = 42.5.
- Tool shows about US 10; UK 9, EU 42.5; JP 27.
Reference table
| Foot | JP | US / UK / EU |
|---|---|---|
| 24.0 cm | JP 24 | US 6.5 / UK 5.5 / EU 38 |
| 25.0 cm | JP 25 | US 7.5 / UK 6.5 / EU 39.5 |
| 26.0 cm | JP 26 | US 8.5-9 / UK 7.5-8 / EU 41 |
| 27.0 cm | JP 27 | US 10 / UK 9 / EU 42.5 |
| 28.0 cm | JP 28 | US 11 / UK 10 / EU 44 |
Limits
- Guideline math only. Lasts vary widely.
- Men's offsets; women's vary by maker.
- Widths unmanaged by length alone.
- Socks shift fit half sizes.
Common mistakes
- Converting US to EU directly.
- Trusting one old size forever.
- Measuring sitting unloaded.
- Ignoring width entirely.
- Skipping maker charts.
Try it yourself
Quick checks. Answers sit tucked under each question.
25 cm foot?
Inches 25/2.54 = 9.84. US 3x9.84-22 = 7.53, about US 7.5. UK 6.5. EU (250+13.5)/6.67 = 39.5. JP 25.
24 cm foot?
Inches 24/2.54 = 9.45. US 3x9.45-22 = 6.35, about US 6.5. UK 5.5. EU (240+13.5)/6.67 = 38. JP 24.
Questions
What is Mondopoint/JP sizing?
JP equals foot cm (Mondopoint). Here JP 27 at 270 mm.
How is US size figured?
About 3x inches minus 22, rounded to halves. Here 9.89 reads US 10.
How is UK size figured?
About one down from US men's: US 10 reads UK 9.
How is EU size figured?
Paris-point math near (mm+13.5)/6.67: 270 mm reads EU 42.5.
Are conversions exact?
Yes. ISO 19407 calls conversions guidelines: lasts and widths shift half to full sizes.
Should I measure or trust old sizes?
Yes. Measure both feet standing, fit the larger, and check maker charts.