What Is Sizing Like at UGG? Your Complete Guide to Getting the Right Fit

By Ella Blake — Fashion Stylist | Tellar Fashion Hub — Always honest, unbiased & unsponsored

UGG sizing runs large — particularly in their classic boots — and for most styles you should size down by half a size, though slippers and sneakers tend to be more true to size. If you've ever ordered a pair of Classic Shorts online, excitedly ripped open the box, and then shuffled around your kitchen like you've borrowed your dad's wellies, you'll know exactly why getting your UGG size right matters before you buy.

I've been recommending UGG to clients for years — there is genuinely no better option for a certain kind of luxurious, cosy-yet-effortless winter dressing — but I've also spent a fair amount of time explaining why "just order your usual size" doesn't quite work here. Let me break it all down properly.

Understanding UGG's Sizing System

UGG is a US brand, which means all their sizing originates in US measurements. For UK shoppers, this creates an extra layer of translation. UGG does produce a UK size guide, but even when shopping directly on ugg.com/uk, you'll notice their sizing defaults are US-based. Always check which sizing system the retailer is displaying — it varies more than you'd expect.

Here's a quick conversion table to use as your starting point:

UK SizeUS SizeEU Size353546365737.56838.5794081041.591142.5

Classic Boots: Size Down Half a Size

This is the rule that catches most people out. The UGG Classic Short, Classic Tall, and Classic Mini — the boots that basically defined a decade of winter dressing — are all cut quite generously. The sheepskin lining compresses with wear, which means a boot that feels slightly snug at first will mould to your foot perfectly after a few days. If you start with a boot that feels immediately comfortable in the shop, it will be sloppy within a fortnight.

If you're a UK 5 (US 7), order a US 6.5 or try the UK 4.5 if available
If you're between sizes, always go down
Wide feet are the one exception — those with a wider fit often find their true size works better

Slippers: Stick to Your True Size

The UGG Scuffette, Ansley, and Fluff Yeah slides are a different story. Slippers are designed with a looser fit already built in, so the sizing logic flips — order your true UK size. I wear a UK 5 in the classic boots (after sizing down from a 5.5) but a UK 5 in the Scuffette, and they fit like a dream. The sheepskin footbed in the slippers also compresses slightly less dramatically than in the tall boots.

Sneakers and Fashion Trainers: True to Size

UGG's trainer range — including the Ca:Go sneaker and the Tasman X — fits true to size. These have a more structured last than the sheepskin boots, so the usual size-down rule doesn't apply. Order your standard UK size and you'll be fine.

UGG Clothing and Accessories: Standard UK Sizing

UGG have expanded significantly into clothing and accessories — their fleece sets, loungewear, and shearling jackets are genuinely gorgeous. Their clothing follows standard US sizing, which translates as follows:

UGG LabelUK SizeEU SizeXS6–834–36S8–1036–38M12–1440–42L14–1642–44XL16–1844–46

The fleece sets in particular come up slightly generous through the body — if you're between sizes, go down. I ordered a medium in the Daylie hoodie set and it was absolutely enormous on me; the small fitted perfectly.

Half Sizes at UGG

UGG does offer half sizes in many of their boot and trainer styles, which is actually quite unusual and very welcome. If you're a standard half size — say, a UK 5.5 — this is genuinely helpful as it removes a lot of the guesswork. For the classic sheepskin boots, a UK 5.5 (US 7.5) is usually the sweet spot for someone who might otherwise hover between a 5 and a 6.

Buying UGG in the UK

You can buy UGG direct at ugg.com/uk, but they're also stocked widely at John Lewis, Selfridges, ASOS, and Schuh. One thing worth noting: ASOS tends to display UGG in US sizes, while John Lewis uses UK sizing. Always double-check before adding to basket — I've seen clients accidentally order two sizes up because of this exact confusion.

Brands to Try If You Love UGG

Whether UGG is out of budget, out of stock, or you simply want to explore the space — here are my picks across different price points.

High Street Picks

M&S — Their shearling-lined moccasin slippers are genuinely excellent value and come in half sizes. A brilliant everyday alternative to the UGG Ansley.
Next — Solid sheepskin-style boots at a fraction of the price. Their slipper range in particular gets consistently strong reviews and holds up well through the winter.
Fat Face — Great for cosy winter footwear and the kind of relaxed, outdoorsy aesthetic that complements the UGG vibe. Their sherpa-lined styles are particularly good.
Joules — Excellent for shearling-trim boots and cosy outdoor footwear. Their sizing tends to be accurate and they do a great range of half sizes.
Seasalt Cornwall — A brilliant option if you love the UGG aesthetic but want something with a more British, coastal feel. Their boot range is solid and well-priced.
Boden — Lovely shearling-lined footwear options and a comfortable fit. Their quality is impressive for the price point and they size quite generously.
White Stuff — Known for cosy, well-made winter footwear that holds its shape. Their slipper boots are a cult favourite among customers and well worth a look.

Premium Picks

Mint Velvet — Their shearling-style boots hit that sweet spot between high street and designer. A more polished, grown-up aesthetic than UGG but with the same level of comfort.
Reiss — For UGG's clothing-adjacent loungewear and knitwear, Reiss is the natural step-up. Their fleece and shearling pieces are beautifully cut and surprisingly versatile.

Independent Picks

Celtic & Co. — A fantastic British brand from Cornwall that makes stunning genuine sheepskin boots and slippers. Completely sustainably sourced and the quality is extraordinary — honestly rivals UGG on every front and supports British manufacturing.
Shepherd of Sweden — A Scandinavian brand making incredibly well-crafted sheepskin footwear that has quietly built a devoted following. Their sizing is more structured than UGG's and runs true — no sizing-down required.

Never Guess Your Size Again — Try Tellar

UGG sizing is a classic example of why generic size guides just don't cut it. Whether you're shopping for boots, slippers, or their clothing range — getting the right size depends on the specific style, not just the brand. That's exactly the problem Tellar was built to solve.

Tellar is the UK's leading clothing sizing tool — match your measurements to 1,500+ brands instantly, including UGG. No downloads. Always free.

Measure once — bust, waist, and hip, or use an existing brand size you trust
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Visit Tellar.co.uk Try the Store Size Lookup Tool

Tellar Fashion Hub — honest, independent, unsponsored. Always free.