Does No.21 Run Big or Small? Sizing Guide & What to Buy

Tailored Meets Edgy: But What’s the Fit Like at No.21?

No.21 — or Numero Ventuno — is the cult Milanese label founded by Alessandro Dell’Acqua. It’s known for mixing masculine tailoring with feminine elements: think sequinned skirts styled with oversized shirts, or clean-cut blazers paired with sheer knits. Loved by fashion editors and minimalist dressers alike, the brand sits at the intersection of runway polish and modern wearability.

But if you’re shopping online, one issue still causes hesitation:Does No.21 run big or small?

🧵 Want your fit matched in seconds?tellar.co.uk and instantly discover your correct No.21 size — plus your size in 1,500+ fashion brands. One-time setup, always free, and includes a printable measuring tape. We’ve analysed every single brand’s size data — so you never have to guess again.

No.21 Sizing: Runs Small in Most Tailored & Fitted Pieces

No.21’s aesthetic favours structure, precision and Italian cuts — which often means slimmer shoulders, narrower sleeves, and tighter waists. Across both men’s and women’s collections, many pieces run small, particularly in blazers, trousers, and buttoned styles.

Women’s Fit Overview

Shirts & Blouses: Often run small, especially through the shoulders and chest. Size up for comfort.
Tailored Dresses: Sleek but fitted — size up if curvier through the hips or bust.
Trousers & Skirts: High-waisted and narrow, especially in woven fabrics. Slim through the hips.
Oversized Jumpers & Knits: Designed to be loose — true to size, occasionally generous.

Men’s Fit Overview

Tailored Shirts & Blazers: Slim Italian fit — runs small for most UK builds.
Trousers: Fitted at the waist and thigh. Size up for more relaxed leg lines.
T-Shirts & Sweatshirts: Usually true to size, but often short in length.

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Why No.21 May Feel Smaller Than Expected

There are three reasons shoppers often find No.21 tighter than expected:

Italian sizing — closer to EU fit conventions than UK vanity sizing
Tailoring DNA — much of the collection draws from traditional menswear cuts
Use of structured fabrics — many styles use satin, poplin, wool, or gabardine with no stretch

That means even items that look fluid on the model may feel close-fitting in real life.

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Tellar Community Fit Feedback

Item TypeRuns SmallTrue to SizeRuns LargeWomen’s Shirts✅✅Tailored Dresses✅✅Blazers & Coats✅✅Knitwear✅✅Men’s Trousers✅✅

🧵 Related Tellar.co.uk sizing guides for similar brands:

What’s Worth Buying from No.21?

1. Structured Shirts & Oversized Poplins

Clean lines and crisp cottons. Size up in traditional styles. For oversized pieces, true to size.

2. Tailored Dresses with Unexpected Detailing

Often fitted and architectural. If you have a fuller bust or hips, size up for comfort.

3. Coats & Wool Blazers

Beautifully tailored with sharp lines. Go up a size if layering or if you have broad shoulders.

4. Knitwear & Pullovers

These tend to be more relaxed and true to size, particularly in mohair or cashmere blends.

5. Embellished Skirts & Evening Trousers

Signature No.21 — strong shapes and luxe finishes. Slim through the hip, so size up if needed.

🧵 tellar.co.uk

Key Fit Tips for No.21 Buyers

Structured = size up: any garment made of satin, poplin, or suiting will run slim
Watch the shoulders: women’s shirts and dresses are cut narrow through the back
Double-check length: men’s tees and some trousers run shorter than expected
Oversized doesn’t mean generous: many pieces look oversized but still fit tight at pressure points

🎯 tellar.co.uk

Why Tellar.co.uk Is Essential for Buying No.21

Designer labels like No.21 don’t follow standard UK sizing. And with luxury pricing, a sizing mistake can be costly. That’s why Tellar.co.uk helps you shop smarter:

✅ Real-world sizing mapped to your body measurements
✅ One-time setup = access to 1,500+ brand fits instantly
✅ Built-in size conversion for UK / EU / IT / US
✅ Always free to use — no login needed to view your results
✅ Free printable measuring tape included

🧵 Create your Tellar profile now and check your No.21 size instantly

Related Brand Fit Guides You’ll Love

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Final Verdict: Does No.21 Run Big or Small?

Shirts, dresses and tailored items run small
Trousers and skirts are slim-cut, especially at the waist and hips
Knitwear and oversized styles are more forgiving
Sizing up is often the safe choice, especially in fitted pieces

Still unsure? Don’t rely on assumptions — let Tellar.co.uk give you real-time accuracy, tailored to your measurements.