Boston Size Guide: Fit, Width & Size Chart
Runs half-size large
The Birkenstock Boston runs half-size large. Start by checking half a size down from your usual UK size. Available in standard (D) width only. Use the table below to convert foot length in millimetres into UK, US Men, US Women, EU, CM; foot length is the stable measurement every size system shares.
Does the Boston run true to size?
Across our sourced data, the Birkenstock Boston runs half-size large. Start by checking half a size down from your usual UK size.
Boston size conversion chart
| Foot length | UK | US Men | US Women | EU | CM |
|---|---|---|---|---|---|
| 252.9mm | 7 | 8 | 9.5 | 38 | 25.5 |
| 257.1mm | 7.5 | 8.5 | 10 | 39 | 25.5 |
| 261.3mm | 8 | 9 | 10.5 | 39 | 26 |
| 265.5mm | 8.5 | 9.5 | 11 | 40 | 26.5 |
| 269.8mm | 9 | 10 | 11.5 | 40 | 27 |
| 274mm | 9.5 | 10.5 | 12 | 41 | 27.5 |
| 278.2mm | 10 | 11 | 12.5 | 42 | 28 |
| 282.5mm | 10.5 | 11.5 | 13 | 42 | 28.5 |
| 286.7mm | 11 | 12 | 13.5 | 43 | 28.5 |
| 290.9mm | 11.5 | 12.5 | 14 | 44 | 29 |
| 295.2mm | 12 | 13 | 14.5 | 44 | 29.5 |
EU sizes round to whole numbers; treat the EU column as the closest honest match.
Boston width availability
Available in standard (D) width only.
Only the standard (D) width is listed, so very wide or very narrow feet may need to adjust length or choose a wider brand.
Fit notes
Use the fit offset and width list together: the size label gives the baseline, while this model-specific fit data tells you what to check first.
Where this data comes from
Built from 1 source · 520 measurements. See how we calculate for how confidence is scored. · Last verified: Jun 2026
- Aggregated reviews n=520 verified 2026-06-21
confidence: 50%