Does ASOS Run Big? The Complete Sizing Guide You Need

Why ASOS Sizing Is So Generous

ASOS deliberately cuts their garments with a relaxed, oversized aesthetic in mind. Their design team aims for that effortless, slightly slouchy look that's become synonymous with contemporary fashion. However, this approach can be frustrating when you're expecting a more fitted silhouette.

The brand also caters to an international market with varying size expectations. What reads as a UK size 12 might need to accommodate different body proportions across their global customer base, leading to this generous approach to sizing.

Category-by-Category Breakdown

Tops and Knitwear

This is where ASOS sizing runs most large. Their oversized t-shirts are genuinely oversized, and even their "fitted" styles tend to be quite roomy. I always advise clients to check the chest measurements rather than relying on the size label. You'll often find better-fitting alternatives at Zara (known for their precise European sizing), COS (minimal, architectural cuts that run true to size), or Mango (Spanish brand with consistently reliable sizing).

Dresses

ASOS dresses are particularly tricky because the generous sizing can make fitted styles look shapeless. For special occasions, I'd recommend looking at Reiss (sophisticated cuts with excellent tailoring), Ted Baker (known for feminine, well-structured dresses), or Whistles (contemporary British brand with consistent sizing) for more predictable fits.

Jeans and Trousers

Surprisingly, ASOS denim runs closer to true size, though still slightly generous in the waist. For comparison, M&S (reliable, classic fits), Next (consistent high street sizing), and H&M (trend-focused but size-accurate) offer more reliable trouser sizing.

Brand Recommendations by Price Point

High Street Alternatives

If you're drawn to ASOS's aesthetic but frustrated by their sizing, try French Connection (edgy, contemporary pieces with reliable fits) and All Saints (rock-chic aesthetic with consistent sizing). Anthropologie offers bohemian-inspired pieces similar to ASOS's vintage-style items but with more predictable sizing.

Premium Options

For elevated basics similar to ASOS's minimalist pieces, consider Me&Em (luxury basics with excellent fit consistency) or LK Bennett (sophisticated British brand known for quality and fit). Jigsaw offers contemporary pieces with European influences and reliable sizing.

Luxury Investment Pieces

When you want that fashion-forward ASOS aesthetic in premium quality, look to Ganni (Danish brand with playful, contemporary designs) or & Other Stories (sophisticated Scandi aesthetic with consistent European sizing).

My Professional Sizing Tips

Always measure yourself before ordering from ASOS. Their size guides are actually quite accurate—it's just that their cuts are generous. Focus on the bust, waist, and hip measurements rather than the size label.

Read the reviews religiously. ASOS customers are usually honest about sizing, and you'll often see comments like "ordered my usual size 10, fits like a 14."

Consider the fabric. Stretchy materials will be more forgiving, while structured pieces like blazers will show the oversized cut more obviously.

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This is exactly why I recommend tellar.co.uk, the UK's leading sizing tool that matches your body to over 1,500 brands instantly. No more size guide frustration or costly returns!

How Tellar Works:

1. Measure once using your bust, waist, hip measurements, or input your existing brand size

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The Bottom Line

ASOS sizing runs large across most categories, particularly in their own-brand items. While this creates that relaxed, contemporary aesthetic they're known for, it means you'll likely need to size down. Always check measurements, read reviews, and consider using Tellar's sizing tool to take the guesswork out of online shopping entirely. Your wardrobe—and your wallet—will thank you for avoiding those frustrating returns.