What Is Sizing Like at ASOS Design?

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

ASOS Design runs slightly generous — generally true to size, but with a relaxed, contemporary fit that can feel a touch bigger than you'd expect from other UK high street brands. For most garments, you can shop your usual size with confidence, but there are definite category quirks you need to know about before you click Buy.

I've been ordering from ASOS for well over a decade — long before half the brands they now stock even existed. It's genuinely one of my first ports of call when I'm hunting for something trend-led at a decent price. But I'll be honest: I've had some spectacular sizing mishaps along the way. There was a particularly mortifying incident involving a midi dress for a friend's birthday dinner, a desperate wrestle to get it over my hips in a restaurant toilet, and a very long Uber home. All because I didn't check the product reviews for that specific style. Live and learn.

The thing with ASOS is that it's not just one brand — it's a massive marketplace. When you're shopping ASOS Design specifically (their own-label range), you're working with one set of standards. But the moment you stray into the third-party brands they stock, all bets are off. This post is focusing specifically on ASOS Design, so let's dig in.

How Does ASOS Design Sizing Generally Run?

Across the board, ASOS Design sits in that sweet spot of true-to-size with a slightly more relaxed cut than, say, Topshop used to. It's often compared to H&M in terms of consistency — reasonably reliable, but with some variation between categories. Their sizing is more generous than River Island (which tends to run small) and more fitted than their own COLLUSION line, which is deliberately oversized.

Tops & knitwear: Generally true to size. Fitted styles may come up slightly snug across the shoulders if you're broader — size up if you're between sizes.
Dresses: This is where it gets interesting. Bodycon and fitted styles tend to run small — I'd always go up a size here. Shift dresses, smock styles, and anything oversized will run large. Read the description carefully.
Jeans & trousers: Mostly true to size, with good stretch in their skinny and slim cuts. Wide-leg styles are cut more generously, so don't panic if they look enormous on the hanger.
Jackets & coats: True to size or slightly generous. If you're layering underneath, you generally won't need to go up.
Occasion & tailoring: Size up by one, particularly in structured pieces. Their blazers can be cut quite narrow across the back.

The ASOS Petite, Tall, Curve & Maternity Ranges

This is where ASOS Design genuinely earns its stripes — and why I recommend it to so many of my clients who struggle with standard sizing. These sub-ranges aren't just a length adjustment and call it a day. They actually redesign the proportions:

ASOS Petite (5'3" and under): Shortened sleeve lengths, higher rises, adjusted bodices. Much more thoughtfully done than most high street petite ranges.
ASOS Tall (5'9" and above): Longer bodies, not just longer hems. The torso proportions are genuinely recalibrated.
ASOS Curve (UK 18–30): Adjusted bust, waist, and hip measurements — not just a scaled-up standard size. Sizing is consistent within the range.
ASOS Maternity: Standard sizing with generous bump allowance. Most clients find their pre-pregnancy size works well throughout.

My Honest Advice: Always Check the Reviews

ASOS introduced customer reviews a few years back and it genuinely changed my shopping experience. Before that, it was a bit of a lottery. Now, if a bodycon midi is running small or a blazer is cutting awkwardly across the shoulders, someone will have said so. I check the reviews religiously before buying anything fitted, and I'd urge you to do the same.

Also — and I cannot stress this enough — watch the catwalk video if it's available. It shows the garment in motion, on a real body, without the smoke-and-mirrors of editorial photography. You can immediately tell if a dress is pulling, if trousers are gaping at the back, or if a top is sheer in a way that wasn't obvious from the product shots. It takes thirty seconds and could save you a return.

Where to Shop If ASOS Design's Sizing Isn't Quite Right For You

ASOS Design is brilliant for trend-led pieces at an accessible price, but it's not for everyone. Here are my picks at every tier — all worth knowing for your wardrobe:

🛍 HIGH STREET ALTERNATIVES

Whistles — Slightly more refined fit with excellent quality control. True to size with a grown-up, polished edge. Great for investment high street pieces.
River Island — Runs small across most categories, particularly fitted styles. Always size up one. Brilliant for jeans and going-out looks.
H&M — Very similar sizing profile to ASOS Design. Reliable true-to-size with a wide range. Good for basics and transitional pieces.
Abercrombie & Fitch — Now dramatically improved in fit and quality. Runs slightly small. Excellent for premium-feel casual wardrobe staples.
All Saints — Runs true to size with a directional, edge-led aesthetic. Their leather jackets and tailoring are particularly well-cut.
Urban Outfitters — Strong overlap with ASOS Design's customer. Sizing can be US-influenced, so always check the measurements. Brilliant for vintage-inspired pieces.
Phase Eight — Brilliant for occasion wear. True to size with a more generous cut through the body — particularly good if you find ASOS's occasion dresses too narrow.
Boden — Surprisingly good for trend-led basics with excellent sizing consistency. Runs true to size. A bit more classic but the quality is outstanding for the price.

✨ PREMIUM PICKS

Reiss — Exceptional sizing consistency. Runs true to size in tailoring and slightly generous in knitwear. Worth every penny for workwear and occasion.
Me&Em — A brilliant step up from ASOS Design if you're looking for longevity in your wardrobe. True to size with a premium, refined cut throughout.

💎 LUXURY & DESIGNER

Max Mara — The gold standard for tailoring. Runs true to European sizing. Their coats are an investment worth making at least once — and the fit is impeccable.

Two Independent Brands Worth Knowing

I always like to flag a couple of left-field finds — these aren't the obvious names, but they deserve a place in your edit:

Ghospell — A contemporary independent brand that's stocked on ASOS but has its own direct channel too. Their sizing is incredibly consistent, their aesthetic is fresh and modern, and they actually publish garment measurements rather than just standard size guides. A genuine hidden gem.
Lucy & Yak — An independent UK brand with a properly inclusive size range (XS–5XL) and brilliant size transparency. Their dungarees and wide-leg trousers are particularly well loved. If you find ASOS's casual range too trend-chasing, Lucy & Yak offers something more considered and characterful.

🔍 Never Guess Your ASOS Size Again — Use Tellar

This is exactly why Tellar.co.uk exists. ASOS stocks over 850 brands alongside ASOS Design — and every single one sizes differently. Tellar matches your exact measurements to your precise size across 1,500+ brands instantly. Measure once, shop with confidence forever.

Enter your bust, waist, and hip measurements — or use an existing brand size you trust
Use the Store Size Lookup tool to find your precise fit in ASOS, COS, Reiss, Arket, and over 1,500 more brands
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Plus, explore the Tellar Fashion Hub — a free library of honest, unsponsored style advice from our team of stylists. No ads. No affiliate bias. Just genuinely useful fashion content.

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