Why Doesn't Birkenstock Make a UK Size 6?
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Short answer: Birkenstock builds its shoes on European lasts, not UK ones. EU 39 measures 250mm and EU 40 measures 260mm. A true UK 6 would sit at roughly 255mm — exactly between the two — and Birkenstock doesn't make a last at that length. So when the EU sizes are converted to UK labels, the run goes straight from UK 5.5 to UK 7 with nothing in between.
It isn't a mistake, and it isn't that size 6 has sold out. There is no UK 6 anywhere in the range.
So what should I buy if I'm a size 6?
Most of our size 6 customers go for the EU 39. That's the one we'd recommend if you want a normal, true fit. If you prefer a little more room, or you're between sizes and tend to size up, step to the EU 40.
One thing worth knowing: Birkenstock's footbed is meant to have a small amount of space around the toes. Your toes should not reach the front edge. So an EU 39 that feels slightly roomy is fitting correctly, not fitting large.
Birkenstock UK to EU size chart
| UK size | EU size | Length |
|---|---|---|
| 4.5 | 37 | 240mm |
| 5 | 38 | 245mm |
| 5.5 | 39 | 250mm |
| — no UK 6 — | — | ~255mm |
| 7 | 40 | 260mm |
| 7.5 | 41 | 265mm |
| 8 | 42 | 270mm |
The full range, including men's sizes and both width fittings, is on our Birkenstock size guide.
Do Birkenstock do a size 6 at all?
No. Not in any style, and not in either width. If a UK 6 is listed anywhere, it's a retailer's own conversion of the EU 39 or EU 40 rather than a size Birkenstock manufactures.
Don't forget the width
Getting the width right matters more than agonising over 39 versus 40. Birkenstock make most core styles in two fittings, and the names are misleading:
- Regular is genuinely wide. It suits wider feet.
- Narrow is closer to a standard fit. Most women between UK 3 and UK 7 want narrow.
If you're a size 6, narrow is the more likely fit. Browse our narrow fit Birkenstock sandals.
We list both the UK and EU size and the width on every product, so you can see exactly what you're ordering.
Still not sure?
If you're between sizes or buying a style you've not worn before, email us at sales@brookfieldcomfort.com and we'll tell you what we'd send. We've been fitting Birkenstocks since 2017.
Shop the Birkenstock Arizona, or see all Birkenstock.