VESTLY · FREE TOOL
Your shoe sizes, in the right chart.
Compare adult EU, UK and US shoe sizes using Nike and adidas charts. Start with both feet or a known size, check neighboring rows and the effect of measurement uncertainty, then keep your reference sheet. The calculator is free, needs no account and processes your entries on your device.
The shoe size reference
246 mm
Nike · EU 40 / UK 6 / US 8.5
adidas · EU 40 / UK 6.5 / US 8
Your comparison
The longer foot measures 246 mm. In the Nike women’s chart, 246 mm falls between the 245 and 250 mm rows: the higher row gives EU 40 / UK 6 / US 8.5. For adidas, the same length maps to EU 40 / UK 6.5 / US 8. This difference explains why a universal conversion can mislead. With ± 2 mm, the rows to check may change.
Keep this result
Measurements and the sheet name stay on this page. Nothing is saved automatically. Only an export you request creates a file on your device.
Measure, compare, try on
- Place each foot on paper secured to the floor. Measure from heel to longest toe with a vertical pencil. Use the same unit for both feet.
- Enter your ruler’s uncertainty, for example ± 2 mm. This setting is not extra room to add inside a shoe.
- Read the equal or next higher chart row and its neighbors for each brand. Between adidas rows, the choice depends on the fit you want; Nike recommends the larger size. Check the specific model and try the shoes on.
An example: 24.2 cm and 24.6 cm
The longer foot measures 246 mm. In the Nike women’s chart, 246 mm falls between the 245 and 250 mm rows: the higher row gives EU 40 / UK 6 / US 8.5. For adidas, the same length maps to EU 40 / UK 6.5 / US 8. This difference explains why a universal conversion can mislead. With ± 2 mm, the rows to check may change.
A few rows to compare
| Foot (mm) | Chart | EU | UK | US |
|---|---|---|---|---|
| 245 | Nike · Men | 40 | 6 | 7 |
| 250 | Nike · Men | 40.5 | 6.5 | 7.5 |
| 245 | Nike · Women | 39 | 5.5 | 8 |
| 250 | Nike · Women | 40 | 6 | 8.5 |
| 246 | adidas · Men | 40 | 6.5 | 7 |
| 250 | adidas · Men | 40 2/3 | 7 | 7.5 |
| 246 | adidas · Women | 40 | 6.5 | 8 |
| 250 | adidas · Women | 40 2/3 | 7 | 8.5 |
Method and sources
Values were checked against the official guides on October 23, 2026. We use foot length, never the Nike label’s “CM / JP” column as a real foot measurement. Displayed sizes come from published rows: no universal formula, interpolation or extrapolation. The result separates the central reference from measurement uncertainty. The adidas chart lists both women’s and men’s conversions.
Checked and updated: October 23, 2026. Independent tool, not affiliated with Nike or adidas.
Who is this for, and what are its limits?
This sheet covers the two brands’ adult charts within the published range shown here. It does not measure width or volume, cover children’s sizes or predict the fit of a specific model. A known size provides a chart reference, not a measurement of your foot. Outside the available rows, we show a limit rather than invent a size. If a shoe feels tight or uncomfortable, do not rely on the number alone.
Shoe size questions
Does EU 39 always mean the same US size?
No. The conversion depends on the brand’s chart and whether you select the women’s or men’s table. Choose both before comparing.
Should I measure both feet?
Yes. The tool uses the longer measurement and shows the difference. Nike asks you to measure both feet; adidas recommends measuring toward the end of the day.
Why does the CM on my Nike box differ from my ruler?
Nike states that label CM / JP is not foot length in centimeters. Measurement mode uses only the “Foot length” row.
What if I am between sizes?
Check both rows shown and the specific model’s guide. Nike recommends the higher row; adidas distinguishes a snug fit from a loose fit. The tool does not impose a universal allowance.
Can I reopen my sheet later?
Save the JSON project and open it in this tool. CSV and PDF keep a readable comparison but do not restore the settings.
Why can a known size produce a range?
Some UK or CM / JP values appear in more than one Nike chart row. All matching rows are retained instead of picking one arbitrarily.
Continue building your outfit
- Casual chic: the simple formula for looking polished every day
- Flat Shoes and Dressy Outfits: How to Create a Polished Pairing
- Midi skirt and shoes: put together an outfit that feels good in motion
A Vestly tool · calculations on your device