How Do Sneakers and Shoes Really Fit? Brand-by-Brand Fit Notes

Size charts tell you which number to order. They don’t tell you whether a brand’s toe box runs narrow, whether the upper stretches, or whether you should size up half a size. This guide covers that — real, brand-by-brand fit notes for every brand Cecile Milan carries, distilled from our in-depth fit testing. For the raw US/UK/EU/CM conversion numbers, see our complete size chart for every brand.

Nike

Nike shoes generally run true to size in length, but the shoe last tends to be narrow, especially through the toe box. Most wearers find that ordering their usual size works for length, but that the fit feels snug width-wise compared to brands built on a roomier last. Wide-width options exist for select models like the Pegasus and Revolution, though even these tend to run narrower than wide-width shoes from competitors like New Balance or Brooks. Flyknit uppers, used across several Nike lines, create a closer, sock-like fit that hugs the foot rather than a traditionally structured one. For wide feet, sizing up half a size is a common recommendation rather than relying on the wide-width option alone.

Nike shoes generally run true to size in length; the fit issue is width, not length.
The last is narrow, particularly in the toe box, across most Nike running and lifestyle models.
Wide-width versions exist for select models like the Pegasus and Revolution, but still run narrower than wide options from New Balance or Brooks.
Flyknit uppers create a close, sock-like fit rather than a structured one.
Wide feet often do better sizing up half a size rather than relying on the wide-width option alone.

Adidas

Adidas sizing depends heavily on which type of shoe you’re buying, not on the brand as a whole. Classic lifestyle sneakers like the Samba, Gazelle, Campus, and Stan Smith run true to EU size with a consistent, slightly roomy last, so most people can order their usual size with confidence. Performance running models such as the Ultraboost and the Adizero racing line tend to run about half a size long, which means sizing down 0.5 EU from your normal size usually gives a closer fit. Training shoes like the Powerlift and Dropset fit true to length but use a narrower last, so wide-footed buyers often go up half a size for comfort. The short version: check which Adidas family you’re buying before assuming your usual size will work everywhere.

Lifestyle sneakers (Samba, Gazelle, Campus, Stan Smith) run true to size with a roomier toe box, though the profile is slim.
Running shoes (Ultraboost, Adizero) tend to run about half a size long — size down 0.5 EU if you want a snugger fit.
Training shoes (Powerlift, Dropset) run true to length but use a narrower last — go up half a size if you have wide feet.
Leather uppers (Stan Smith, Superstar) stretch and mold with wear; knit uppers like Primeknit hold their shape, so the out-of-box fit is closer to the final fit.
Adidas running shoes tend to run slightly longer than the Nike equivalent in the same size, so don’t assume your Nike size carries over exactly.

New Balance

New Balance generally fits true to size to slightly roomier than Nike, so if you wear a Nike size 9, trying a New Balance in the same size or half a size down is a reasonable starting point. Compared to Adidas, sizing is close, though some wearers find Adidas runs a touch bigger. The catch is that New Balance sizing is not consistent across every model — some silhouettes run small, others run large — so the honest answer depends on which shoe you are buying, not just the brand.

As a brand, New Balance tends to fit true to size or slightly roomier than Nike.
Sizing versus Adidas is close, but some wearers size down slightly when switching from Adidas to New Balance.
Model matters more than brand: the 574 tends to run small, while the 530 and 9060 tend to run large.
New Balance offers up to six width options (from extra-narrow to extra-extra-wide) on many styles, which is wider selection than most Nike or Adidas models.
When in doubt on a specific model, check that model’s own reviews rather than relying on a brand-wide rule.

Jordan

Jordan sizing questions come up more than almost any other topic in sneaker shopping, and for good reason: get it wrong on a limited or resale pair and you’re often stuck with it. The good news is that Jordan sizing isn’t random — it follows a few clear, model-specific patterns once you know what to look for. Here’s how to get it right the first time.

Hoka

Most HOKA shoes fit true to size, but the brand’s overall sizing is not consistent across every model — it depends heavily on which shoe you’re buying. Recovery and max-cushion models like the Bondi tend to run slightly small or snug, so many wearers size up half a size. Everyday trainers like the Clifton and race-oriented shoes like the Mach X are widely reported as true to size with no adjustment needed. Trail shoes like the Speedgoat run notably narrow through the midfoot, regardless of length. If you have wide feet, HOKA does offer wide and extra-wide options on several popular models, including the Bondi, though not every silhouette comes in extended widths. The safest approach is to check the specific model’s fit notes rather than assuming one HOKA size rule applies to the whole lineup.

HOKA sizing varies by model — there is no single “HOKA runs big” or “HOKA runs small” rule that applies to the whole brand.
The Bondi tends to run small or snug; many wearers size up half a size for a more comfortable recovery fit.
The Clifton, Mach X, and Rincon are widely reported as true to size with no adjustment needed.
The Speedgoat and Arahi run narrow through the toebox, even for people whose length sizing is otherwise correct.
Wide and extra-wide options exist for several popular models, including the Bondi, but not for every HOKA silhouette.

Asics

Most ASICS lifestyle sneakers (Gel-1130, Gel-NYC) fit true to size, so ordering your usual number is the safe default. Running-focused models are a different story: because feet swell during longer efforts, many runners size up half a size in shoes like the Gel-Nimbus, GT-2000, or Novablast to leave room for that swelling and for toe splay. Width adds another layer – some ASICS uppers run roomier (the Gel-NYC’s softer construction accommodates wider feet well), while others run snugger through the forefoot (the Gel-Kayano 14 in particular). There isn’t one universal “ASICS runs big” or “ASICS runs small” answer – it depends on whether you’re buying a lifestyle pair or a running pair, and which specific model.

Lifestyle ASICS models (Gel-1130, Gel-NYC, Japan S) generally fit true to size – order your usual number.
Running models (Gel-Nimbus, GT-2000, Novablast) are commonly sized up half a size to accommodate foot swelling on longer runs.
Width varies by model, not just by brand: Gel-NYC runs roomier, while Gel-Kayano 14 can feel tight through the forefoot for wider feet.
Extended widths (2E, 4E) exist on select running models but are rarely offered on lifestyle pairs.
Measure your foot at the end of the day, when it’s at its largest, for the most reliable sizing decision.

On

Most On Cloud running shoes run true to size for everyday wear, so ordering your usual size is a safe starting point. Where it gets more specific is width and model: the Cloud 6 and Cloudflyer fit close to true-to-size with secure heel containment, the Cloudmonster offers a touch more forefoot room, and several independent reviewers describe On’s overall toe box as narrower than brands like Nike or ASICS, paired with a roomier heel — which is why switching from a wider running shoe sometimes calls for going half a size down rather than staying at your usual size. If width, not length, is the issue, sizing up isn’t the fix; a wider model or the men’s version (which some women with broader feet use for its naturally roomier last) works better.

Most On Cloud models run true to size for casual and everyday wear — start with your usual size.
If you’re coming from Nike Flyknit or ASICS and those feel slightly tight, going half a size down in On is a common adjustment.
On’s toe box runs narrower than average, with a comparatively roomier heel — a width issue, not a length issue.
Don’t size up to solve a width problem; choose a roomier model (like the Cloudmonster) or the men’s version instead.
The Multisport collection fits roomier than the core Running collection, aimed at runners used to cushioned brands like Brooks or HOKA.

Salomon

Salomon shoes generally run narrower and slightly smaller than mainstream sneaker brands like Nike, Adidas, or HOKA, so most people switching from another brand should size up half a size. This applies across both trail-running models and Salomon’s lifestyle sneakers, though the exact fit varies by model: some, like the Speedcross, get an almost universal recommendation to size up half a size, while others, like the XT-6, run true to size for most feet and only need sizing up for wide feet or the Gore-Tex version. Because Salomon is a French brand, it’s also worth checking sizes using centimeter-based charts rather than assuming US sizing converts cleanly.

Salomon runs narrower than most mainstream brands, largely due to its Sensifit system, which creates a snug, locked-in midfoot fit by design rather than by sizing error.
If you normally wear Nike, Adidas, or HOKA, sizing up half a size is the most common adjustment when switching to Salomon.
Trail and running models often need extra room for foot swelling during activity, so sizing up half a size is common advice even for people who find Salomon true to size in casual wear.
Fit varies by model: the Speedcross almost universally needs a half size up, while the XT-6 and XT-4 run closer to true to size for most feet.
If you’re between sizes, the general recommendation is to size up rather than down, since Salomon’s snug midfoot design leaves little room to size down comfortably.

Birkenstock

Birkenstock uses its own European sizing scale that doesn’t map onto US sizing the way most sneaker brands do, which is the single biggest reason first-time buyers get it wrong. As a rough conversion, add 31 to your US women’s size or 33 to your US men’s size to land on the EU size — so a US women’s 8 is roughly an EU 39, and a US men’s 9 is roughly an EU 42 — but the more reliable approach is trying the two width options: Regular, which suits medium to wide feet, and Narrow, which fits most women’s feet and is the standard recommendation for around 80% of women shoppers. Once you have the right width and size, expect roughly ¼ inch of space around your foot, with the cork footbed molding to your foot shape over two to three weeks of wear.

Birkenstock sizing is EU-based: add roughly 31 to your US women’s size, or 33 to your US men’s size, to estimate the EU equivalent.
Two widths are offered — Regular (medium to wide feet) and Narrow (narrow to medium feet, the standard fit for about 80% of women).
Birkenstocks are generally described as fitting true to size once you’ve picked the right width, though sizing can be confusing the first time due to the EU conversion.
Aim for about ¼ inch of space around your foot, or more precisely, roughly 10mm behind the heel and 5mm in front of the toes.
The cork footbed takes about 2–3 weeks to fully break in; leather uppers take longer to stretch than Birko-Flor synthetic uppers.

UGG

Most UGG boots run true to size, but they feel noticeably snug for the first week or two of wear. That’s by design: the sheepskin lining is meant to compress and mold around your foot, and it typically loses about 5-8% of its loft after 10-15 hours of use. If you buy your usual size and the boots feel tight across the top of your foot on day one, that’s normal and it will ease. UGG slippers and casual shoes are a different story – they run true to size from the first wear, with no meaningful break-in period, so you can size them the same way you’d size a regular pair of sneakers.

Classic sheepskin UGG boots run true to size but fit snug for roughly 1-2 weeks while the lining compresses.
UGG slippers and non-sheepskin styles fit true to size immediately, with no break-in adjustment needed.
If you plan to wear thick socks regularly, size up half a size rather than buying a larger boot outright.
UGG offers wide options – “D” widths for women’s styles and “EEE” for men’s – for feet that need more room side to side.
Don’t size down to compensate for the initial snugness; it will loosen on its own as the wool packs down.

Frequently Asked Questions

Should I size up or down if I’m between two sizes? As a general rule, size up for running and trail shoes (feet swell on long efforts), and size true-to-size for lifestyle sneakers unless a brand’s notes above say otherwise.

How is this different from the size chart guide? The size chart guide converts US/UK/EU/CM numbers. This page explains fit behavior — width, stretch, break-in — that a conversion table can’t show.