What’s My Clothes Size at COS? Does COS Run Big or Small?

COS (Collection of Style) is renowned for its architectural silhouettes, premium fabrics, and minimalist Scandinavian design. As part of the H&M Group, COS offers elevated basics and fashion-forward tailoring that appeals to customers who favour clean lines and quality craftsmanship.

But its sizing can leave shoppers guessing. So, does COS run big or small? Why is sizing at COS sometimes confusing? And what’s the best way to know your correct size in real-time?

This guide explores the reality behind COS sizing—and how Tellar.co.uk, the UK’s leading free sizing tool, helps you shop COS confidently and accurately.

Does COS Run Big or Small?

COS typically runs large—particularly in tops, shirts, and outerwear.

The brand intentionally leans into:

Oversized silhouettes
Boxy cuts
Dropped shoulders
Relaxed tailoring

While this is part of the aesthetic, it means shoppers often find COS garments feel roomy or voluminous, even when labelled as their standard UK size.

However, trousers and structured dresses can run true to size or slightly small, especially in woven fabrics.

COS Sizing: Designed Differently

Unlike most high street brands that follow the body closely, COS prioritises form and flow over fit. This design philosophy results in garments that:

Skim the body rather than cling
Offer more volume in the torso, sleeves, and legs
Avoid overt shaping (e.g. darts, defined waistbands)

This works beautifully for a minimalist silhouette—but can make sizing unpredictable for those unfamiliar with the brand.

Fit Observations by Category

Garment Type	COS Fit Style	Sizing Recommendation
T-Shirts & Blouses	Oversized / boxy	Consider sizing down
Knitwear	Relaxed fit	True to size or size down
Trousers	True to size / slim fit	Stick to usual size
Dresses	Voluminous or shift	Size down if between sizes
Tailored blazers	Structured shoulders	True to size or size up if busty
Coats	Oversized by design	Often size down for fitted look

COS vs Other Brands

COS differs significantly from brands like:

Reiss or Massimo Dutti, which use close-fitting European tailoring
Next or M&S, which offer more traditional UK high-street cuts
Zara, which leans narrow and structured

COS’s modern silhouettes and loose grading mean that a UK size 10 shopper might wear an 8 or even a 6 in COS shirts or jackets—but need a 10 or 12 in trousers or tailored dresses.

Why COS Size Charts Aren’t Enough

The standard COS size chart lists:

UK Size	EU Size	Bust (cm)	Waist (cm)	Hips (cm)
8	34	80	64	88
10	36	84	68	92
12	38	88	72	96
14	40	92	76	100

But the chart doesn’t reflect:

The oversized nature of most tops and coats
The fabric (e.g. stiff cotton vs. stretchy jersey)
Whether the garment was designed in Stockholm, Paris, or another design hub

That’s why shoppers often order the wrong size—especially online.

Common COS Sizing Issues

Broad-shouldered customers may find the armhole placement awkward in drop-shoulder tops
Petite shoppers can feel overwhelmed by the volume of wide-leg trousers or longline coats
Curvier body types may find some tailored pieces tight at the hip or bust, despite an otherwise relaxed design

Tellar.co.uk: Your COS Sizing Answer

Tellar.co.uk is the UK’s most advanced free sizing tool. It uses your actual body measurements to match you with the correct size across COS and over 1,500 brands.

No more relying on broad charts. No more second-guessing a COS shift dress or oversized shirt. Just clean, real-time sizing matched to your shape and the specific garment type.

How It Works

Visit www.Tellar.co.uk
Create your free profile (only once)
Enter your bust, waist, and hips (in cm or inches)
Select COS from the brand list
Instantly view your best-fitting COS size across every garment category

Tellar is continuously updated with brand-specific logic and fabric types—so it knows whether a COS top is intentionally oversized or cut slim.

Why Tellar Works So Well for COS

✅ Oversized Style Awareness

Tellar factors in whether a piece is cut oversized, slim-fit, or structured.

✅ Fabric-Sensitive

It adjusts sizing based on material—e.g. non-stretch cotton, lyocell, or wool blends.

✅ Body-Proportion Matching

Your unique shape drives the recommendation—not just bust or hip alone.

✅ Works Across Brands

Once your profile is saved, you can get your sizes instantly across COS, Zara, Massimo Dutti, Whistles, Reiss, and more.

✅ Free Forever

No hidden costs. No subscriptions. Just reliable, accurate sizing—always.

Example: COS Size Matching

Measurements:

Bust: 90cm
Waist: 73cm
Hips: 100cm

Tellar might recommend:

COS oversized shirt: UK 8
COS tailored trousers: UK 12
COS shift dress: UK 10
COS knit jumper: UK 8 (relaxed fit)

Each result includes a short explanation based on fit logic and garment type.

COS Isn’t One-Size-Fits-All—But Tellar Makes It Feel That Way

Because COS sizing is intentionally fluid and design-led, static charts won’t tell you what will actually fit. Tellar does the work by interpreting:

Cut
Fabric
Body shape
Intended silhouette

So you never have to over-order again.

Final Thoughts

COS sizing runs large by design, but that doesn’t mean every item will feel the same. Tops, coats and shirts often fit oversized, while trousers and structured garments stay true to size.

Instead of guessing, use Tellar.co.uk to match your body to COS’s fit philosophy in seconds. No returns. No surprises. Just accurate sizing across every piece.

“Find your size in 1,500+ brands real-time. It’s Free & Easy.”

Try it now:

👉 Create your free profile
👉 Log in anytime to view your size instantly