COS vs Whistles vs Jigsaw: What’s the Difference in Sizing?

COS, Whistles, and Jigsaw are three premium high-street brands in the UK that serve fashion-conscious shoppers looking for quality, style, and cut—but their sizing systems differ significantly. If you've ever been a size 10 in one and a size 12 in another, you're not imagining things. These brands use different fit models, grading rules, and design philosophies.

Here’s how each brand sizes their collections and how to find the best fit—plus how Tellar.co.uk eliminates the guesswork by matching your body to every store.

Overview: Brand Fit Philosophy

Brand	Fit Type	Core Audience	Style Signature
COS	Oversized / Relaxed	Minimalist, unisex-inspired	Scandinavian structure, volume
Whistles	Tailored Contemporary	Urban professionals, clean silhouettes	True-to-size, slightly fitted
Jigsaw	Traditional / Feminine	Classic British wardrobe	Smart tailoring, waist-focused

1. COS Sizing: Relaxed & Scandinavian Minimalism

Key Points:

COS uses European sizing and designs with oversized, androgynous fits
Fit can vary dramatically by item: a size 10 in a structured blazer may be huge in a cocoon coat
Tops and dresses tend to run large across the chest and shoulders
Trousers are often cut wide with long inseams

Common Fit Experiences:

Body Type	COS Fit Insight
Petite	May feel swamped—size down or shop cropped cuts
Hourglass	Loose fits may lack waist definition
Tall	Excellent for longer arms and torsos

✔️ Sizing Tip: Start one size down from your normal UK size for relaxed-fit items unless specifically tailored.

Example: If you're a UK 12, COS relaxed-fit pieces may feel better in a size S or EU 38.

2. Whistles Sizing: Modern, True-to-Size Structure

Key Points:

Whistles aligns closely to standard UK sizing
Dresses, tops and trousers are usually cut for a neat fit
Waist and bust fit true for most women; sleeves can run narrow in tailored blouses

Common Fit Experiences:

Area	Fit Detail
Shoulders	Slightly structured—good for defined builds
Waist	Often nips in slightly—true to label size
Trousers	High-rise, consistent sizing

✔️ Sizing Tip: Take your regular UK size. If you're between sizes (especially busty), size up in tailored styles.

Example: A UK 12 shopper with a fuller bust might find better comfort in a 14 blouse, but trousers will often fit true.

3. Jigsaw Sizing: Traditional, Feminine British Fit

Key Points:

Jigsaw pieces are tailored with a classic hourglass form in mind
Dresses are designed to accentuate the waist
The fit is consistent across their trousers, dresses, and coats
Slightly more generous than Whistles in the bust and hip

Common Fit Experiences:

Body Type	Fit Advantage
Pear	Skirts and dresses often accommodate hips
Hourglass	Dresses and coats follow natural waistlines
Apple	May need to size up for waistless silhouettes

✔️ Sizing Tip: Go with your standard UK size but check waist vs hip ratio on tailored dresses.

Side-by-Side Size Comparison (UK 12)

Brand	Bust (cm)	Waist (cm)	Hip (cm)	Fit Note
COS	92–96	74–78	98–102	Can feel oversized in relaxed styles
Whistles	94	76	100	Most true-to-size of the three
Jigsaw	96	78	104	Slightly generous hip cut

How the Fit Differs by Garment Type

✅ Trousers

COS: Wide-leg, pleated, long rise—best for tall/column builds
Whistles: Structured trousers, great officewear
Jigsaw: Slightly softer tailoring, fits curvier hips better

✅ Dresses

COS: Loose shapes, dropped waists, tunic styles
Whistles: Cinched waists, great for hourglass or rectangle figures
Jigsaw: Midi-length, fit-and-flare cuts flatter pear and hourglass bodies

✅ Outerwear

COS: Oversized trench, robe and cocoon styles
Whistles: Clean tailoring, double-breasted shapes
Jigsaw: Belted coats and wrap styles to define waistline

Why Sizes Feel So Different

Grading Rules
Each brand uses a different “fit model” to base their sizing scale. COS fits on a taller frame, Whistles on a standard UK 10-12, and Jigsaw on a curvier UK 12 silhouette.
Design Ethos

COS focuses on structure, not curve
Whistles blends minimalism with shape
Jigsaw retains feminine British tailoring with emphasis on proportion

Fabric & Construction

COS uses heavy, sculptural fabrics that drape away from the body
Whistles leans into silk, wool blends, and clean finishes
Jigsaw uses stretch-enhanced blends to maintain tailoring with comfort

Use Tellar.co.uk to Match Sizing Across All Three

Rather than juggling size charts and returns, let Tellar.co.uk match your bust, waist and hips to the right size in each brand.

Whether you’re comparing COS trousers to Whistles jeans or a Jigsaw coat to a COS dress, Tellar knows how each one fits—backed by real data from over 1,500 fashion brands.

Here’s how it works:

✅ Input your measurements once (or select a brand you already wear)

✅ Tellar instantly calculates your correct size in COS, Whistles, and Jigsaw

✅ Perfect for online orders and cutting down returns

Get Started Now:

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Conclusion:

COS, Whistles, and Jigsaw each offer a unique fit profile. COS runs relaxed, Whistles is structured and true to size, and Jigsaw leans feminine with generous hips and tailored waists. Use Tellar.co.uk to know exactly what size you are in each—instantly and for free.

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