靴のサイズの国際コンバータ

The Shoe Size International Converter translates shoe sizes between US (with separate men's and women's scales), UK (closer to men's US − 0.5), EU (Continental Europe, 33-49+), JP/CM (Japanese, in centimeters of foot length), and Mondopoint (ISO 9407 international standard, foot length in millimeters). Each system uses different measurement bases and offsets, so conversion is essential for online international shopping. The calculator includes separate tables for men's, women's, and children's shoes since sizing differs significantly between genders — US Women's 8 is NOT equivalent to US Men's 8 despite the same number. Shoe sizing has a complex history. The English system dates to 1324 when King Edward II decreed that 3 dried barleycorns = 1 inch, and barleycorn-length increments became the basis for UK shoe sizes still used today. The Continental European system uses 'Paris Points' (1 Paris Point = 6.66mm = 2/3 cm). The Japanese system uses centimeters of foot length directly (most intuitive). The Mondopoint system (ISO 9407, 1981) uses millimeters of foot length and width — the most accurate but rarely used commercially despite being international standard. Gender-specific differences exist because men's and women's foot anatomy differs on average: women have narrower heels, higher arches, wider forefoot relative to heel, and the average woman's foot is about 1.5 sizes smaller than the average man's. US sizing reflects this with separate scales (Women's 8 ≈ Men's 6.5). UK and EU sizing typically uses one scale but indicates men's or women's specific lasts (foot shape molds). The calculator handles this complexity with separate gender tables to avoid confusion. This calculator helps you convert between all major shoe sizing systems for accurate international shopping. Select gender category (women, men, kids), enter your size and source system, and the calculator outputs equivalents across US, UK, EU, JP/CM, and Mondopoint. The most accurate input method is foot length in cm — measure your foot heel-to-longest-toe barefoot and use that for universally comparable sizing. Brand and style variations remain significant — always check brand-specific sizing charts before committing to online purchases.

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1. 1Step 1 — Select Gender/Age Category: Choose Women (separate US Women's scale), Men (separate US Men's scale), or Kids (C for child, Y for youth — different size scales within kids category). This selection determines which reference table the calculator uses.
2. 2Step 2 — Enter Shoe Size and Source System: Enter your size and select system. US is most common in North America. UK and EU widely used internationally. CM is most intuitive (just your foot length). Mondopoint is rarely used in retail but most accurate.
3. 3Step 3 — Calculator Finds Closest Match: Calculator looks up the table row matching your input. Each row has US, UK, EU, CM equivalents for the same physical foot size. Outputs all systems plus Mondopoint (CM × 10 = MP in mm).
4. 4Step 4 — Measure Your Foot for Most Accurate Results: Stand on paper, mark heel and longest toe (usually big toe). Measure heel-to-toe in cm. Add 0.5-1cm for comfortable shoe fit (toes need room to move). Enter that measurement with 'CM' source system for universal conversion.
5. 5Step 5 — Check Brand-Specific Sizing: Generic conversion is a starting point, but brand variation is significant. Nike runs small. New Balance runs wide. Italian designer brands run narrow. Always check brand size chart and read reviews about fit before committing online.
6. 6Step 6 — Measure Both Feet — They Often Differ: Many people have asymmetric feet differing by ½ size. Always buy for the larger foot. Measure both, take the larger. Some brands offer split-size purchases for significant asymmetry, but most require ordering for the larger foot and accepting some looseness in the smaller.

• !Using men's table for women's shoes — sizes are not interchangeable (Women's 8 ≠ Men's 8).
• !Confusing kids' C (child) and Y (youth) — different size scales within kids category; Y often labels closer to adult sizing.
• !Measuring foot in shoe — measure barefoot; add 0.5-1cm for comfortable shoe fit.
• !Ignoring brand-specific sizing — Nike, Italian designers, and athletic shoes vary significantly from generic conversions.
• !Not measuring both feet — asymmetry is common; always buy for the larger foot.