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 US size. Available in standard (D) width only. Use the table below to convert your foot length in millimetres straight to US, UK, EU and CM sizes — the one measurement every system agrees on.

Best fit recommendation for Birkenstock Boston

For a 274 mm foot, Birkenstock Boston runs large. Best fit: US 10 (likely US 9–11), UK 9, EU 40, 27 cm — confidence 50%.

Recommended size for a 274 mm foot on Birkenstock Boston (best fit + range, not a guarantee)
Best fit Likely range UK EU CM Confidence
US 10 US 9–11 9 40 27 50%

Evidence: 1 sources · no lab measurement in this record

See how we calculate for the methodology. Sizes vary by model and foot shape; this is an estimate, not a guarantee.

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Does the Boston run true to size?

Across our data the Birkenstock Boston runs half-size large. Start by checking half a size down from your usual US size.

Boston size conversion chart

Boston sizes by foot length. US Men's, US Women's, UK, EU and CM. The highlighted row is the model's true-to-size anchor.
Foot length US Men US Women UK EU CM
252.9mm 8 9.5 7 38 25.5
257.1mm 8.5 10 7.5 39 25.5
261.3mm 9 10.5 8 39 26
265.5mm 9.5 11 8.5 40 26.5
269.8mm 10 11.5 9 40 27
274mm 10.5 12 9.5 41 27.5
278.2mm 11 12.5 10 42 28
282.5mm 11.5 13 10.5 42 28.5
286.7mm 12 13.5 11 43 28.5
290.9mm 12.5 14 11.5 44 29
295.2mm 13 14.5 12 44 29.5

EU sizes are always rounded to a whole size — treat the EU column as the closest honest match.

Boston width availability

Available in standard (D) width only.

Only the standard (D) width is offered, so very wide or very narrow feet may need to adjust length or choose a brand with more width grades.

Expert fit notes

Clog runs large on US scale. Size down half to full once footbed conforms.

Where this data comes from

Built from 1 source and 520 measurements. See how we calculate for how confidence is scored.