How Do Designer Clothes Sizes Compare to High Street Clothes?

When you're shopping between high street favourites like Zara, H&M, or Next and luxury labels like Gucci, Prada or Dior, it's easy to assume that a size 10 is a size 10—right?

Wrong.

The truth is, there’s no industry-wide sizing standard, and nowhere is that more obvious than when comparing designer vs. high street clothing sizes. If you've ever bought a UK 12 in Topshop and struggled to zip up the same size in a Burberry dress, you're not imagining things.

This guide explains how designer sizing compares to high street sizing, why the disparity exists, and how you can shop smarter using Tellar.co.uk—the UK’s most accurate size-matching tool.

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🧵 What’s the Difference Between Designer and High Street Sizing?

Let’s break it down:

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🎯 Why Are Designer Clothes Often Smaller?

1. Design Philosophy

Designer garments are tailored to fashion models or slimmer fit standards. Think runway proportions: narrow hips, long torsos, small waists.

2. Country of Origin

Most luxury labels use French or Italian sizing, which generally runs one or two sizes smaller than UK equivalents. For example:

• A UK 10 is often an IT 42 or FR 38

• But an IT 42 may fit more like a UK 8 depending on the brand

3. Exclusivity Factor

Smaller sizes create a perceived exclusivity. Luxury fashion, historically, wasn’t designed with inclusivity in mind.

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📦 High Street Brands: Mass Appeal, Mass Confusion

High street brands like Mango, ASOS, Marks & Spencer, and Primark are made for broader audiences. That means:

• More vanity sizing (e.g. labels marked UK 10 that measure like UK 12)

• Larger available size ranges (UK 6–22+)

• Faster production cycles = less consistency

Even within the same high street store, a size 12 blazer may fit nothing like a size 12 dress.

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📏 Examples of Real Sizing Differences

These numbers are approximate and depend heavily on the garment type. But they highlight the mismatch between sizes and expectations.

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🛠️ So How Can You Shop Smarter?

It’s no longer enough to go by the label. What you need is brand-specific sizing matched to your exact body measurements.

That’s exactly what Tellar.co.uk does.

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✅ Tellar.co.uk: The UK’s Most Accurate Size-Matching Tool

We’ve built a tool that:

• ✅ Takes your chest, waist, and hip measurements

• ✅ Matches you to your best-fitting size in over 1,500 fashion brands

• ✅ Works for both designer labels and high street stores

• ✅ Tells you your correct size in each specific store

You can enter your actual measurements OR tell us your known size in one store, and we’ll calculate the others.

🎯 Try the store size lookup tool now

🧵 Create your free profile

📏 Download a free measuring tape

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📲 Compare Sizes Across Brands with a Click

Scenario 1:

You wear a UK 12 in ASOS

You want to buy from Selfridges (Vivienne Westwood dress)

With Tellar:

You enter your ASOS size

Tellar instantly tells you what size you are in Vivienne Westwood, based on their chart and your fit profile

Scenario 2:

You measured your chest: 92 cm, waist: 75 cm, hips: 100 cm

Tellar matches you to:

• M&S: UK 12

• Zara: UK 14

• Gucci: IT 46

• Reiss: UK 12 (narrow fit)

You’ll never have to wonder again.

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💬 Designer vs High Street: Summary

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📌 Follow Tellar for Weekly Size Hacks

We post daily sizing comparisons, charts, infographics and more on:

• 📷 Instagram – @Tellar.co.uk

• 📌 Pinterest – Tellar.co.uk

• 💼 LinkedIn – Tellar.co.uk

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🚀 Final Word

Designer brands and high street shops do not size the same—and it’s not your body that’s the problem, it’s the chart.

With Tellar.co.uk, you can shop confidently across labels without the confusion, the measuring tape, or the guesswork.

✔ Accurate

✔ Brand-specific

✔ Always free

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