Why Standard Size Charts Don't Work
EU 42 in Nike is not the same as EU 42 in Adidas. Each brand uses different shoe molds ("lasts"), which means the same number can mean different actual lengths. Here's proof:
| Foot Length | Nike US | Nike EU | Adidas US | Adidas EU |
|---|---|---|---|---|
| 25.5 cm | 7.5 | 40.5 | 7.5 | 40.7 |
| 26.0 cm | 8 | 41 | 8 | 41.3 |
| 26.5 cm | 8.5 | 42 | 8.5 | 42 |
| 27.0 cm | 9 | 42.5 | 9 | 42.7 |
| 27.5 cm | 9.5 | 43 | 9.5 | 43.3 |
| 28.0 cm | 10 | 44 | 10 | 44 |
That's why generic "EU to US" converters give wrong answers. You need brand-specific charts.
Method 1: Wall + Ruler (Most Accurate)
This takes 30 seconds and gives you accuracy within 1-2mm.
- Stand on a hard floor, heel touching the wall. Wear thin socks or go barefoot.
- Place a ruler (or tape measure) on the floor, from the wall towards your toes.
- Read the measurement at the tip of your longest toe (not always the big toe).
- Measure both feet — use the larger number.
- Measure in the afternoon — feet swell during the day, just like when you walk in shoes.
Your number is in centimeters. Multiply by 10 to get millimeters (e.g., 27.0 cm = 270 mm).
Method 2: Paper Trace
- Stand on a sheet of paper on a hard floor.
- Trace around your foot with a pen held vertically.
- Measure the longest distance from heel to toe on the outline.
This method is slightly less accurate (±2-3mm) but works without a wall.
Method 3: Credit Card Reference (No Ruler Needed)
A standard credit card is exactly 85.6 mm long. Use it as a reference:
- Stand with heel against the wall.
- Place the credit card next to your foot on the floor.
- Count how many card-lengths fit from wall to toe.
- Multiply:
card-lengths × 85.6 = foot length in mm
Example: 3.15 cards × 85.6 = 269.6 mm ≈ 270 mm.
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Find My Size in 149 Brands →Common Mistakes to Avoid
| Mistake | Why It Matters | Fix |
|---|---|---|
| Measuring while sitting | Foot is shorter unloaded — you'll get a size too small | Always stand with full weight on foot |
| Measuring only one foot | Most people have one foot larger | Measure both, use the bigger number |
| Morning measurement | Feet swell 3-5mm during the day | Measure in the afternoon |
| Thick socks | Adds 2-3mm to measurement | Measure barefoot or in thin socks |
| Rounded numbers | "About 27 cm" could mean ±5mm | Measure to the nearest millimeter |
Size Conversion Table (Men's, Top 8 Brands)
| Foot (cm) | Nike | Adidas | New Balance | Hoka | ASICS | Brooks | Puma |
|---|---|---|---|---|---|---|---|
| 25.5 | US 7.5 | US 7.5 | US 7.5 | US 7.5 | US 7.5 | US 7.5 | US 7.5 |
| 26.0 | US 8 | US 8 | US 8 | US 8 | US 8 | US 8 | US 8 |
| 26.5 | US 8.5 | US 8.5 | US 8.5 | US 8.5 | US 8.5 | US 8.5 | US 8.5 |
| 27.0 | US 9 | US 9 | US 9 | US 9 | US 9 | US 9 | US 9 |
| 27.5 | US 9.5 | US 9.5 | US 9.5 | US 9.5 | US 9.5 | US 9.5 | US 9.5 |
| 28.0 | US 10 | US 10 | US 10 | US 10 | US 10 | US 10 | US 10 |
Data from manufacturer size charts. US sizes vary by brand despite the same number — EU sizes show the real differences.
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Get My Size Passport →FAQ
Q: What's the most accurate way to measure foot size at home?
A: The wall + ruler method. Stand with your heel against a wall, measure to the tip of your longest toe. This gives accuracy within 1-2mm.
Q: Should I measure my foot in mm or cm?
A: Millimeters are more precise. 270 mm is more useful than "about 27 cm." FitScan accepts both.
Q: How do I know if I have wide feet?
A: Measure the widest part of your foot. For men, wider than 100mm is considered wide (2E). For women, wider than 90mm. See brand-specific width guides.
Q: My two feet are different sizes. Which one should I use?
A: Always use the larger foot. It's better to have slightly more room than to have toes pressing against the front.