The fastest way to get your Birkenstock size right is to measure your foot length in centimeters and match it against Birkenstock's whole EU sizing β not the shoe size you'd normally grab off a Philippine sneaker shelf. Birkenstock only comes in whole EU sizes (no half sizes), and the footbed is cut roomier through the toes than most everyday shoes, so a straight size-for-size swap from your usual brand often runs big. This guide walks through measuring your foot, converting to EU, fit notes for each model, and what to do if a pair still doesn't feel right.
Why doesn't my regular shoe size work for Birkenstock?
Birkenstock sizing is built around foot length in millimeters, not the size labels used by sneaker or dress-shoe brands, and it only comes in whole EU sizes β no half sizes to split the difference. Combined with the roomier toe box, this is why someone who normally wears a men's 10Β½ in a Philippine sneaker often ends up in a Birkenstock men's 9Β½ (EU 42) instead of sizing "the same." Measuring your foot directly, rather than converting from a size label, is the more reliable route.
How do I measure my foot for the right size?
- Stand on a piece of paper against a wall, weight evenly on both feet (do this in the evening, when feet are slightly more swollen β closer to how they'll feel after a full day standing or walking).
- Mark the wall edge at your heel and the tip of your longest toe.
- Measure the distance between the marks in centimeters.
- Repeat for both feet β use the larger measurement.
- Match that length to the EU size chart below, then check the per-model notes for any width adjustment.
Birkenstock EU-to-US size conversion chart
Birkenstock sizes are split by width line β Regular fit and Narrow fit β not just by gender, so the same EU number can carry a different US size and footbed width depending which line you're in. All three confirmed charts below:
Women's Β· Narrow fit
| EU Size | US Size | Footbed Length | Footbed Width |
|---|---|---|---|
| 35 | 4 β 4.5 | 225 mm | 85 mm |
| 36 | 5 β 5.5 | 230 mm | 87 mm |
| 37 | 6 β 6.5 | 240 mm | 89 mm |
| 38 | 7 β 7.5 | 245 mm | 91 mm |
| 39 | 8 β 8.5 | 250 mm | 93 mm |
| 40 | 9 β 9.5 | 260 mm | 95 mm |
Regular fit is Birkenstock's men's/unisex last; Narrow fit is the women's and kids' last β see the note below the tables on switching lines if you need a wider or narrower fit than your gender's default.
Men's Β· Regular fit
| EU Size | US Size | Footbed Length | Footbed Width |
|---|---|---|---|
| 40 | 7 β 7.5 | 260 mm | 99 mm |
| 41 | 8 β 8.5 | 265 mm | 101 mm |
| 42 | 9 β 9.5 | 270 mm | 102 mm |
| 43 | 10 β 10.5 | 280 mm | 103 mm |
| 44 | 11 β 11.5 | 285 mm | 107 mm |
| 45 | 12 β 12.5 | 290 mm | 109 mm |
Notice EU 40 shows up in both charts above with a different US size and a different footbed width (95mm Narrow vs. 99mm Regular) β that's the width line doing the work, not a typo. It's why "just convert the EU number" isn't quite enough on its own.
Do Birkenstocks run narrow or wide? What if I have wide feet?
Regular fit is Birkenstock's men's/unisex last β wider through the toes β and Narrow fit is the women's and kids' last, trimmed by roughly 4β7mm at the same EU size. They're not two options sitting side by side within one gender's line; each gender defaults to its own last. Where this matters for fit: if you're a woman with wider feet and a Narrow-fit pair feels tight across the ball of the foot, many unisex styles (Arizona, Boston) are also stocked in Regular fit, and sizing into that men's/unisex version is a common, legitimate fix β not a workaround.
Does fit vary by model?
Yes β coverage and closure change how forgiving each model is on sizing:
| Model | Fit behavior | Sizing note |
|---|---|---|
| Arizona | True to the EU chart; two adjustable straps | Easiest to fine-tune after purchase β loosen or tighten either strap |
| Boston | Roomier through the instep (closed clog shape) | Some wearers prefer this true-to-size or even half a size down |
| Gizeh | Slimmer, toe-post silhouette | Toe post sits snug β if it feels tight between the toes, try the next size up before sizing down |
| Mayari | Toe loop plus multi-strap | Straps adjust for width; length still follows the EU chart |
| Madrid | Single-strap slide | Buckle adjusts width; no strap on the opposite side, so length accuracy matters more |
What about kids' Birkenstock sizing?
Kids' Birkenstocks come in a Narrow fit line and follow the same foot-length-first logic as adult sizing, just on a smaller scale:
| EU Size | US Size | Footbed Length | Footbed Width |
|---|---|---|---|
| 25 | 7 β 7.5 | 160 mm | 69 mm |
| 26 | 8 β 8.5 | 165 mm | 71 mm |
| 27 | 9 β 9.5 | 170 mm | 73 mm |
| 29 | 11 β 11.5 | 185 mm | 77 mm |
| 31 | 13 β 13.5 | 200 mm | 81 mm |
| 33 | 2 β 2.5 | 210 mm | 85 mm |
Because kids' feet grow quickly and the sizes above skip a number here and there (25, 26, 27, then jumping to 29, 31, 33), measuring every few months β rather than assuming last season's size still fits β is the safer habit.
Will they stretch, and what's the break-in period?
Birkenstock's cork-latex footbed molds to your foot shape over about two weeks of regular wear, which is comfort adjusting to you β not the shoe stretching in length or width. That's why getting the EU size and model fit right at checkout matters more than hoping a snug pair will "give." Wear a new pair a few hours at a time for the first week or two rather than a full day immediately, and the personalized fit develops from there.
What if I order the wrong size?
If a pair doesn't fit once it arrives, Res|Toe|Run accepts returns within 30 days of receipt β reach out through the chat icon on the site with photos and your order reference, and approved returns are refunded as store credit valid for one year. Re-measuring against the chart above before reordering is the quickest way to land on the right size the second time.
FAQs
I'm exactly between two EU sizes β which way should I go?
Size down if the model has adjustable straps (Arizona, Mayari, Madrid), since you can loosen the strap for extra room; size up for closed or snug styles like Boston or Gizeh, where there's no strap to compensate for a tight fit.
Do Birkenstock sizes run the same across all styles?
Length follows the same EU chart across styles, but fit varies β closed styles like Boston run roomier through the instep, while toe-post styles like Gizeh fit slimmer, so the same EU size can feel different model to model.
I have wide feet but wear women's sizing β should I try the men's/unisex fit instead?
Possibly β women's Birkenstocks use the Narrow last, and many unisex styles (Arizona, Boston) are also stocked in the men's Regular last, which runs roughly 4β7mm wider at the same EU size. If Narrow feels tight across the ball of the foot, sizing into the Regular version of the same style is a legitimate fix, not a workaround.
