Introduction

Why Clothing Sizes Vary Across Brands: Zara vs ASOS Explained

Clothing sizing is one of the most frustrating aspects of online shopping. Why does a UK size 10 fit perfectly in Zara but feel too tight at ASOS? Why do brands differ so drastically when it comes to fit, even within the same country or style category?

This comprehensive guide will explore the reasons why sizing varies so much between brands, with a focused comparison between Zara and ASOS. We’ll also show you how to overcome these inconsistencies using Tellar.co.uk — a free sizing platform that provides accurate size recommendations based on your real body measurements.

Brand sizing is not governed by any universal standard. Each brand develops its own sizing philosophy based on internal design decisions, marketing, and target demographic.

For instance, some brands use ‘vanity sizing’ to flatter customers by labeling larger clothes as smaller sizes. Others maintain traditional or narrow fits, which can alienate consumers with broader or curvier body shapes.

This discrepancy results in major confusion for online shoppers — which is exactly what Tellar.co.uk aims to solve: /store-size-lookup/

Zara is known for its fashion-forward, European aesthetic and relatively slim, tailored cuts. Their sizing tends to run small, especially for women’s items.

Key traits of Zara sizing:

- Tailored fits that emphasize form

- Slim trousers and narrow shoulders in tops and jackets

- Some rigid fabrics (like denim or suiting) with minimal stretch

As a result, many UK shoppers find that they need to size up when purchasing from Zara.

ASOS has a broader and more inclusive sizing philosophy. The brand offers Petite, Tall, Curve, and Maternity lines in addition to its core sizing.

ASOS sizing characteristics:

- More relaxed and forgiving cuts in casualwear

- Availability of extended sizes (up to size 30 UK in many items)

- Use of stretchy materials in basics and essentials

ASOS generally runs truer to UK high-street sizing than Zara does.

Zara, based in Spain, typically starts its design process with European measurements and adapts sizing labels for UK, US, and Asian markets. This can lead to tight fits when converting from EU to UK size labels.

ASOS, founded in the UK, starts from a British standard and adjusts its sizes for global distribution.

Tellar.co.uk solves this issue by letting users enter their measurements once and then displaying correct sizes for both Zara and ASOS — and over 1500 other brands: https://tellar.co.uk

Customer data shows:

- Zara sizes often run ½ to 1 size smaller than ASOS in similar garments.

- Zara dresses, blazers, and trousers are more fitted and rigid.

- ASOS items often include stretch or relaxed-fit cuts, reducing sizing errors.

Using the Tellar sizing algorithm, users can directly compare how the same body measurements translate to size recommendations across both brands.

Try it: /store-size-lookup/

Instead of guessing based on size labels, shoppers should rely on actual body measurements.

Measurements needed:

- Chest (bust)

- Waist

- Hips

Once entered on /log-in-page/, these measurements are matched against each brand’s sizing data to return a personalised size recommendation.

Tellar uses a database of brand-specific size charts and fit behaviour. It considers:

- Fabric stretch vs rigidity

- Fit category (oversized, slim, relaxed)

- Regional sizing conversions

It compares your measurements against size thresholds to return the best-matching size in Zara, ASOS, and more than 1500 other labels.

- Free and accurate recommendations in seconds

- Works across Zara, ASOS, Mango, H&M, Reformation, and more

- Mobile-friendly

- Lets users choose between cm or inches

Start your search here: /store-size-lookup/

- Always check fabric type: Zara uses more rigid, non-stretch fabrics

- Size up at Zara if in doubt; stay true to size with ASOS basics

- Check the garment description for notes like "fitted" or "oversized"

- Create a Tellar profile to avoid size guessing: /log-in-page/

Sizing differences between Zara and ASOS are just one example of a widespread issue in fashion retail. But with the right tools, you can shop confidently and avoid costly mistakes.

Tellar.co.uk is your personalized size finder tool for more than 1500 brands, helping you take the guesswork out of online clothing purchases.

👉 Use the tool now: /store-size-lookup/

👉 Save your measurements securely: /log-in-page/

👉 Contact us with questions: /contact/