What Is Sizing Like at arch4? An Honest Cashmere Fit Guide

BY ELLA BLAKE – SENIOR FASHION STYLIST & FOUNDER | TELLAR — ALWAYS HONEST, UNBIASED & UNSPONSORED POST

arch4 broadly follows standard UK sizing across its core XS–XL range, but here's the catch every shopper needs to know: a large chunk of the collection is deliberately designed to sit oversized, with dropped shoulders and generous bodies. So while the size you'd normally take is usually "correct," it often won't give you the fit you're picturing. For a neater, closer line, you'll frequently want to size down.

I've styled a lot of cashmere over the years, and arch4 is one of those London labels people fall hard for the moment they touch it. The baby goat cashmere is spun incredibly fine, so it feels weightless and almost suede-soft. But "luxury knit you'll keep for a decade" only works if the fit is right on day one — so let's get into exactly how it runs.

How arch4 sizing actually works

The label runs a simple XS through XL grid, scaling from roughly a UK 6 at XS up to a UK 14 at XL. In my experience fitting clients, the body measurements themselves are honest and reliable — if you take a UK 10 in most British brands, the M is your starting point and it won't surprise you on the tape measure.

Where arch4 differs from a typical high street jumper is intention. This is knitwear designed in the spirit of quiet, architectural minimalism, and a good portion of the range is cut to drape rather than cling. A few quick pointers:

• Core classics and fitted styles (slimmer crew necks, ribbed polos, finer-gauge pieces) tend to sit true to size and skim the body nicely.

• Statement knits — chunky jumpers, balloon sleeves, brushed cashmere — are built with deliberate volume, so they read at least one size bigger than the label suggests.

• "One Size" pieces do appear, particularly some turtlenecks and accessories, and these are genuinely roomy rather than petite-friendly.

The bit that trips people up: the oversized pieces

This is the single most important thing to flag. Several arch4 styles are described by stockists as intended to be oversized, with the explicit advice to size down if you want a closer fit. The dropped shoulder is the giveaway — when the shoulder seam falls halfway down your upper arm, the garment is meant to be relaxed and slouchy, not fitted.

A little confession from my own wardrobe: the first premium oversized cashmere jumper I ever bought, years ago, I took in my "normal" size because the number felt safe. It swamped me — the shoulders hung, the hem hit an unflattering spot, and I looked like I'd borrowed it from a much taller friend. Lesson learned the expensive way. Now, with any dropped-shoulder arch4 style, I tell clients to go down a size if they're petite or want definition, and stick to size for a true cocoon-like drape.

A quick word on cashmere and fit over time

Fine cashmere relaxes and softens with wear, so it's better to have a knit fit cleanly at first than to "size up for comfort." And please — never hang your cashmere. arch4 (and every good knit) should be folded and dried flat, because hanging drags the shoulders out of shape and quietly ruins the fit you paid for.

My honest styling tips for arch4

• Petite or want a sharp line? Size down on anything with a dropped shoulder or labelled oversized.

• Love a relaxed, tucked-and-loose look? Take your true size and lean into the volume — balance it with a slim trouser or straight-leg denim.

• Buying a turtleneck? Check whether it's a fitted style or a roomy "One Size" before committing, as the difference is significant.

• Investing in a dress or matching set? Go by your hip measurement first; knit dresses cling, so the largest measurement tends to dictate comfort.

Where else to shop cashmere, by budget

arch4 sits firmly at the luxury end, so if you love the look but want options at every price point, here's where I'd genuinely send a client.

On the high street

• M&S — the benchmark for affordable, reliable cashmere; their pure-cashmere jumpers are a perennial best buy and run true to size.

• COS — the closest high street match for arch4's minimalist, architectural aesthetic, often in beautifully clean shapes.

• Hush — soft, easy, slightly relaxed knits that nail the off-duty cashmere look.

• Mint Velvet — relaxed-luxe jumpers with a flattering modern cut.

• Jigsaw — elevated, considered staples in lovely neutral tones.

• Boden — dependable cashmere with a bit more colour and warmth in the fit.

• White Stuff — cosy, characterful everyday knits at gentle prices.

• Massimo Dutti — premium-feeling high street cashmere with a refined, slightly tailored line.

Premium picks

• The White Company — calm, neutral, beautifully made cashmere that suits a pared-back wardrobe.

• Me&Em — clever, modern knitwear with thoughtful proportions and longevity built in.

• Reiss — polished, slightly sharper knits that work hard for desk-to-dinner dressing.

Luxury & designer

• Brora — heritage Scottish cashmere, gorgeous colour stories and a comparable forever-piece feel.

• Max Mara — for when you want designer cashmere with proper tailoring and structure.

Two independents worth knowing

• Navygrey — a small British B-Corp label doing genuinely considered, beautifully simple everyday cashmere essentials in a tight, edited palette.

• &Daughter — a quietly brilliant independent built on traditional British and Irish knitting mills, with timeless silhouettes that age beautifully.

How Tellar takes the guesswork out

Honestly, the reason I built Tellar is moments exactly like the arch4 oversized confusion — where the label is "right" but the fit isn't what you expected. Tellar is the UK's leading sizing tool: you measure once, using your bust, waist, hip, or simply a brand size you already own, and your body is instantly matched to over 1,500 brands. Never squint at a size guide again.

• Measure once — bust, waist, hip, or an existing brand size.

• Use the Store Size Lookup tool to get your precise size in any brand — COS, Reiss, Everlane, Arket and more.

• Always free, no downloads needed — it works straight in your browser.

There's also the Tellar Fashion Hub: a library stacked with free posts from our top stylists. Honest, unbiased, independent and always free — style advice, top picks and the best brands, all in one place.

Find your exact arch4 size in seconds

Stop guessing whether to size down. Match your measurements to 1,500+ brands instantly with Tellar — always honest, always unbiased, always free.

• Get your size: tellar.co.uk

• Try the Store Size Lookup: tellar.co.uk/store-size-lookup