How Do I Size Designer Clothing? A Complete Guide for UK & USA Shoppers

Luxury Sizing Tips | Fit Comparisons | Brand Advice | Tailored Styling | Tellar Sizing Solution

Designer fashion is known for its quality, craftsmanship, and statement appeal—but it’s also notorious for inconsistent sizing. Whether you're shopping for a Saint Laurent blazer, a Zimmermann dress, or a pair of Loro Piana trousers, you’ve probably noticed: your size in designer clothing rarely matches your high street fit.

This in-depth guide breaks down how to size designer clothing correctly, how it differs from UK and US high street brands, and how to find your perfect size using Tellar.co.uk—the UK’s leading real-time sizing tool.

🧵 Why Designer Clothing Sizing Is So Confusing

Designer brands often follow their own internal sizing standards, influenced by the region they’re based in (France, Italy, UK, USA), their heritage fit model, and their aesthetic (oversized vs fitted).

Technical Reasons for Size Differences:

Region of origin: Italian brands (e.g. Gucci, Dolce & Gabbana) tend to run small. French brands (e.g. Celine, Balmain) are often narrow at the shoulders and bust.
Fit philosophy: Designer labels sometimes cut for runway proportions—tall, narrow frames—rather than real-world bodies.
Luxury materials: Non-stretch silks, leathers, or woven wool don’t allow for error in fit.
Label vanity sizing: Some brands intentionally label garments as smaller or larger to flatter their target demographic.

👉 Read: UK vs USA vs European Clothing Sizes – The Ultimate Guide Instruction on Posts

📏 UK vs US vs Designer Sizing Conversion Chart (Women)

UK Size	US Size	French Size	Italian Size
6	2	34	38
8	4	36	40
10	6	38	42
12	8	40	44
14	10	42	46
16	12	44	48

Always check the designer's own size chart before buying, but be aware: listed charts aren’t always aligned to real body measurements. That’s why tools like Tellar.co.uk are so helpful for cross-brand comparison.

How Do I Know My Size in Designer Clothing?

✅ Option 1: Use your measurements

Take bust, waist, and hip measurements using a soft tape measure, then convert using a designer’s size guide (but expect variation).

✅ Option 2: Use a brand you know

If you know you’re a UK 10 in Reiss or a US 4 in Everlane, you can use Tellar’s Store Size Lookup to translate that to The Row, Celine, COS or Ganni.

💎 Top Designer Brands and How Their Sizing Runs

🇮🇹 Italian Brands

Gucci – Runs small; jackets and trousers often tight at the waist.
Dolce & Gabbana – Body-hugging, especially dresses.
Prada – Tailored and narrow through shoulders and bust.

🇫🇷 French Brands

Celine – Slim and structured; choose one size up if in-between.
Chloé – Feminine cuts, slightly forgiving.
Balmain – Often very narrow in arms and waist, especially in jackets.

🇺🇸 American Designer Brands

The Row – Oversized and fluid; often a full size larger than UK high street.
Tibi – Modern tailoring with boxy cuts; stick to your usual size.
Marc Jacobs – Trend-led but generally true to US sizes.

🛒 Designer-Inspired High Street Brands (Better Sizing, Lower Prices)

COS

Sleek, architectural shapes that rival The Row and Celine. Sizes run generous.

👉 What Size Am I in COS?

Reiss

Polished tailoring with French-inspired silhouettes. Runs true-to-size but fitted.

👉 Next Sizing Guide – High Street Comparison

& Other Stories

Wide selection of designer-style dresses, trousers and blouses with moderate price points.

Arket

Refined staples, wool coats and wide-leg trousers. Clean tailoring.

👉 Finding Your Clothes Size – Fit Guide

Styling Tips: Making Designer Pieces Work for You

Tailoring Is Key

Even luxury clothes can benefit from alteration. Focus on the shoulders and waist—don’t be afraid to size up and tailor down.

Invest in Staples

Buy designer when it matters: coats, bags, tailored trousers, blazers. For seasonal tops or trendy cuts, high street can suffice.

Mix High & Low

Pair a designer blazer with COS trousers and a Uniqlo tee. Great style doesn’t require every item to be luxury.

Where Tellar.co.uk Changes Everything

Because sizing varies dramatically across brands and countries, using raw measurements—or guessing—can lead to expensive mistakes. Tellar.co.uk removes this friction entirely.

🔍 How Tellar.co.uk WorksInstruction on Posts

Measure once, using bust, waist, and hip—or enter a known brand/size.
Use the Store Size Lookup Tool to see your size in 1,500+ brands—from Saint Laurent to Reiss.
Shop smarter: no guesswork, fewer returns, more confidence.
It’s always free. No app, no downloads—just in-browser access for instant answers.

The Free Tellar Fashion Hub

Thousands of fit and style articles, written by real stylists—not affiliates or retailers. Always unbiased. Always free.

📏 Sizing Resources:

Garment Fit Guides:

Styling Advice:

📲 Stay Connected with Tellar

Instagram: @Tellarsizing
Twitter/X: @TellarSizing
Facebook: Tellar Sizing
Pinterest: TellarSizing

✅ Final Thoughts

Sizing in designer fashion can be a headache—but it doesn’t have to be. With Tellar.co.uk, you get the exact size recommendation for any brand, designer or high street, based on your personal fit.

UK’s Leading Sizing Tool

Real-Time Brand Matching for 1,500+ Labels

Always Honest. Always Unbiased. Always Free.

Find your size in 1,500+ brands real-time. It’s free & easy.

Get started at Tellar.co.uk