Does COS Run Big? Your Complete Sizing Guide

Yes, COS generally runs large, particularly in tops, dresses, and outerwear – but there's much more to understanding this Scandi favourite than simply sizing down. As someone who's spent years helping clients navigate the sometimes confusing world of COS sizing, I can tell you that their architectural, minimalist approach to design creates beautiful pieces that require a slightly different approach to sizing than your typical high street brands.

The COS Sizing Reality

COS has built its reputation on clean, oversized silhouettes that prioritise form and flow over traditional fitted shapes. This design philosophy means their garments often feel roomier than you'd expect, even when labelled as your standard UK size. It's not poor sizing – it's intentional design that celebrates space and movement.

However, this can leave even seasoned shoppers scratching their heads. I've had countless clients tell me they've ordered their usual size 12, only to receive what feels like a size 16. The key is understanding that COS cuts for straighter body shapes and prioritises architectural lines over body-hugging fits.

Category-by-Category Sizing Breakdown

Tops & Knitwear

This is where COS runs most generously. Their signature organic cotton tees, merino jumpers, and silk blouses are cut with considerable ease. I typically advise clients to size down, especially if you prefer a more fitted silhouette. Their ribbed mock necks and oversized shirts can handle going down a full size whilst still maintaining that effortless, draped look COS is known for.

Dresses

COS dresses vary dramatically. Their shift dresses and flowing midi styles run large – sometimes dramatically so. I've seen clients swimming in their usual size. However, their more structured shirt dresses and tailored pieces tend to run closer to true sizing, though still with that characteristic roominess through the body.

Trousers & Bottoms

Here's where things get interesting. COS trousers, particularly their non-stretch, woven styles, run much more true to size. Their cult-favourite wide-leg trousers and tailored pieces follow more conventional sizing. However, they're cut for straighter hip lines, which can be challenging if you're curvier through the hips and thighs.

Outerwear

COS coats and blazers are designed for layering, so they naturally run large. Unless you're planning to layer heavily underneath, I'd recommend sizing down for a more contemporary fit whilst still maintaining that architectural silhouette they're famous for.

My Professional Styling Tips

After years of working with COS pieces, here's my insider advice: always check the fabric composition. Their 100% cotton pieces tend to have more structure and run closer to size, whilst their lyocell and viscose blends can be more fluid and oversized. Pay attention to the model shots too – COS often styles pieces oversized intentionally, so factor that into your decision.

If you're between sizes, I always recommend going smaller with COS. You can always have pieces taken in if needed, but it's much harder to add fabric. Their quality justifies the occasional tailoring cost.

Where to Find Similar Minimalist Style

High Street Alternatives

ZARA - Offers similar architectural cuts with more predictable sizing and faster trend turnover.

MANGO - Excellent for minimalist pieces with slightly more fitted cuts than COS, perfect for petite frames.

COS - The original! Danish-minimalist aesthetic with quality fabrics and distinctive oversized fits.

WHISTLES - British brand offering contemporary cuts with better sizing consistency and luxurious fabrics.

MASSIMO DUTTI - Spanish sophistication with tailored minimalism, runs more true to size than COS.

REISS - Modern British styling with excellent fit and premium fabrics, ideal for workwear.

ME&EM - Luxury casual wear with impeccable fits and contemporary feminine cuts.

Premium Options

ARKET - H&M's sustainable sister brand offering similar minimalist aesthetic with better size consistency.

EVERLANE - American minimalism with transparent pricing and excellent quality basics.

Designer Level

TOTEME - Swedish luxury minimalism that perfects the Scandinavian aesthetic COS aims for.

THE ROW - Ultimate in minimalist luxury with impeccable tailoring and premium fabrics.

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   For everything you need to know about finding your perfect fit across all brands, check out their Ultimate Clothing Sizing Guide.

   The Bottom Line on COS Sizing

   COS runs large by design, not by accident. Their oversized aesthetic is integral to their Scandinavian minimalist philosophy. Understanding this helps you shop smarter and invest in pieces that truly work for your wardrobe.

   My advice? Start by sizing down, especially for tops and dresses. For trousers, stick closer to your usual size but be prepared for straighter cuts. And when in doubt, use tools like Tellar to take the guesswork out of online shopping entirely.

   COS pieces are investment buys – their quality and timeless design make them worth getting the sizing right. With these insights and the right tools, you can shop COS with confidence and build a wardrobe full of pieces that fit beautifully and last for years.