What Is Sizing Like at Unique 21?

TELLAR FASHION HUB · BRAND SIZING GUIDE

By Ella Blake — Senior Fashion Stylist & Founder | Tellar — Always honest, unbiased & unsponsored post

Unique 21 sits true to size in line with standard UK measurements, although the cuts run on the slimmer, more body-conscious end of the high street — so if you’re between sizes or hover at the top of a size band, you’ll almost always be happier going up by one. Their range tops out at a UK 14 in the main line, with a dedicated Curve collection extending sizing further, and the fits lean towards trend-led tailoring, sharp going-out pieces and figure-skimming dresses rather than relaxed, easy silhouettes.

I’ll be honest with you — the first Unique 21 piece I ever bought was a black blazer dress for a friend’s 40th in Soho, and I made the classic mistake of ordering my usual size 10 without checking the actual centimetre measurements on the product page. It arrived, I zipped it up, and… let’s just say I had a brisk twenty-minute walk around my kitchen trying to convince myself it would “loosen up by Saturday.” It didn’t. A size 12 was sent overnight, it was perfect, and that was the moment I learned to take this brand’s slim cut seriously. So let me save you the panic.

Who Is Unique 21, Really?

Unique 21 is a British label born in 2014, with a design studio focused on clean, minimal tailoring, soft suiting and contemporary occasion pieces. Think tuxedo dresses, wide-leg jumpsuits, boyfriend blazers, corset tops and slip skirts — the kind of pieces you reach for when you need to feel polished but not stuffy. They stock through their own site and across ASOS, Next, Zalando and a handful of other multibrand retailers, which means they’ve become a quiet wardrobe staple for the modern woman who wants high-fashion energy without designer pricing.

Where they win is the cut. Where they trip people up is exactly that same cut.

The Honest Sizing Verdict

Officially, Unique 21 is true to size. Realistically, here’s what I’ve learnt fitting clients into this brand for years:

If you have a smaller bust and slim hips, your usual UK size will fit beautifully.
If you’re fuller in the bust (a C cup or above), size up. Their structured tops and blazers are built on a smaller bust block than M&S or Hobbs.
If your waist-to-hip ratio is pronounced (small waist, curvier hips), fit to your hip measurement and have the waist nipped in later. Trust me on this one.
If you’re tall (5’8” or above), mini dresses really do come up mini. Always check the length on the product page rather than assuming.

“Their cuts hug. That’s the whole point. Buy it for the body you have on the day, not the body you hope to have by Friday.”

How It Fits, Category by Category

Dresses

This is the heart of the brand. Their bodycon, blazer and slip dresses are sharply cut and unforgiving in a fabulous way — they’re designed to skim the body. The fabric across most styles is a structured, lightly stretchy polyester blend, so there’s some give, but not enough to rescue you if you’ve sized down. If you’re ordering an event dress, take your bust and hip measurements seriously. Their slip dresses are arguably their best-kept secret — go true to size for a clean, fluid drape, or size up for that slouchy 90s feel.

Blazers & Tailoring

Where most high street blazers err on the boxy side, Unique 21’s tailoring is more nipped at the waist and narrower across the shoulders. Beautiful if you’re petite-framed or rectangular through the torso, trickier if you’ve got broader shoulders or a fuller bust. My honest recommendation: size up one and have the sleeves shortened by a tailor. Far better fit than buying your size and feeling restricted across the back.

Trousers & Jumpsuits

Their wide-leg trousers and jumpsuits are some of the best-value tailoring on the British high street, but the waistbands run small. I’d size up if you’re between or if your waist measurement leans towards the upper end of a UK size. Jumpsuits in particular benefit from sizing up — the torso length is built for around 5’5”–5’8”, so taller women will appreciate the extra room.

Tops, Bodysuits & Co-ords

Bodysuits run notably snug across the chest, so size up if in any doubt. Their co-ords are cut as a matched set, meaning if your top and bottom sit in different size brackets (which is most of us, frankly), buy the two pieces separately rather than as a “set” — you’ll get a properly tailored look rather than a compromise.

Stylist’s Tips Before You Hit Order

Always check the centimetre measurements on the individual product page. Unique 21 lists garment measurements per item, and they vary surprisingly between collections.
Size up for structured pieces, true to size for slip and jersey fabrics.
Read the model’s height note. Their models are typically 5’8”+, which has implications for how a mini will fall on you.
Returns can be slow. Order in good time before any event — don’t leave it to the week of.

If Unique 21 Isn’t Quite Right — Brands That Sit in the Same Lane

If you love the Unique 21 aesthetic — sharp tailoring, occasion-led pieces, going-out energy — but want to explore something with a slightly different fit, here’s where my clients and I look:

High Street & Premium

Mango — for slightly more generous tailoring with the same modern, minimalist feel. The waistbands on their wide-leg trousers are more forgiving and the bust block runs a touch larger.
Zara — fashion-forward dresses and corset tops on a similar trend cycle, although Zara’s sizing is famously inconsistent so always check the chart per item.
River Island — occasion dresses, sequinned co-ords and bodycon at a comparable price point with a slightly roomier cut through the hips.
Coast — for that polished occasion look but with structured fits that flatter a curvier silhouette better than Unique 21.
Oasis — wedding-guest dresses and tailored separates that lean a little more feminine and floral, with a true-to-size cut.
Warehouse — sharp tailoring, contemporary occasion wear and beautifully cut blazers that suit a broader frame.
French Connection — modern, slightly more grown-up tailoring with excellent dress fabrications.
Reiss — if you want a step up in fabric quality and a more refined cut, this is where I’d send a client investing in a tailored dress for the next decade rather than the next season.

Two Independent Picks I Love

Pretty Lavish — a London-based independent label specialising in considered occasion wear, beautiful slip dresses and elevated knit sets. The fit is closer to Unique 21’s slim aesthetic but with noticeably better fabric weight.
4th & Reckless — another London indie doing modern, body-conscious tailoring and event dressing. Their cut runs slightly more generous than Unique 21, so if you’ve found Unique 21 too snug, this is a brilliant alternative.

Designer / Luxury

Self-Portrait — for the elevated party-dress moment.
Roland Mouret — for sharp, sculpted tailoring at the highest level.

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