How Do I Find My Size in Shackets? A Stylist's Honest & unsponsored Guide

Finding your size in a shacket comes down to your chest measurement, shoulder width, and how you plan to layer underneath — because a shacket that fits beautifully over a thin tee can feel completely strangled the moment you add a chunky knit. I learned this the hard way with an otherwise perfect overshirt that became entirely unwearable once November arrived. Here's what I wish I'd known from the start.

What Even Is a Shacket? (And Why Sizing Is Trickier Than You'd Expect)

A shacket — the shirt-jacket hybrid that has genuinely earned its place as a wardrobe staple — sits in that useful middle ground between outerwear and a top layer. It's not quite a jacket, not quite a shirt, which means brands don't always agree on how to size it. Some treat it like outerwear and cut it generously; others size it like a shirt and cut it closer to the body. You won't always know which camp a brand falls into until you read the product measurements — which is exactly why you need to look beyond the label.

The Measurements That Actually Matter

Before you look at anything else, get these numbers sorted:

Chest/Bust: Measure around the fullest part of your chest with the tape parallel to the floor. This is your primary reference point for shacket sizing.
Shoulder width: From shoulder point to shoulder point across your upper back. An ill-fitting shoulder seam on a shacket is very obvious and very difficult to style your way out of.
Back length: From the top of your shoulder to where you want the hem to fall. Shackets vary wildly here — some hit at the hip, others at mid-thigh.
Arm length: Shoulder point to wrist. Important for avoiding that awkward too-short sleeve situation, especially if you're tall.

Once you have these, always cross-reference with the product's individual measurements rather than just the brand's standard size chart. Many brands publish the flat chest measurement and body length for each piece — use those numbers.

The Layering Question You Must Answer First

This is the question I ask every client before we even look at sizes: what are you actually going to wear underneath this? A shacket worn over a lightweight shirt or jersey top will fit very differently to one layered over a thick knit or a hoodie. If you're buying for transitional weather (wearing it over a tee in September, over a jumper in November), you should factor in at least 5–8cm of ease across the chest. In practical terms, that usually means sizing up one from your usual top size — but it depends entirely on the brand's base fit.

If you're buying a shacket primarily as a lightweight top layer — more shirt, less jacket — stick closer to your actual measurements. If it's doing duty as proper outerwear, size up.

High Street: Where to Shop and What to Expect

Zara — consistently one of the best for shackets, season after season. Their cuts tend to be slightly boxy and oversized by design, so check model height and the size they're wearing. I'd say size down if you're between sizes here.
Mango — great shacket options in both casual and more tailored finishes. Generally cuts true to size, occasionally slightly generous. Their checked and cord styles in particular get excellent press coverage.
ASOS — huge range across fits, lengths, and fabrics. Always use the product-specific measurements rather than their size guide, as fit varies by style and supplier. Particularly good for petite and tall options.
Anthropologie — brilliant for elevated, textured shackets that feel a step above the high street. Their sizing can be slightly Americanised (running larger), so factor that in.
River Island — reliable for on-trend shacket styles at accessible price points. True to size on the whole, with decent variety in sleeve length.
Abercrombie & Fitch — has quietly become one of the best high street destinations for well-cut shackets. Their fits are generous without being sloppy, and quality has improved significantly.
All Saints — for a more directional, slightly edgier take. Their shackets often come up slim across the shoulder, so broad-shouldered women may want to size up. Excellent fabric quality at the price point.

Premium Picks Worth the Investment

Barbour — if you want a shacket that will outlast every trend, Barbour's overshirt styles are the ones to consider. Sizing tends to be generous and accommodating for layering. A proper investment piece.
Massimo Dutti — beautifully cut shackets in quality fabrics. Sizing is precise and fairly European, so those with a fuller bust may want to size up. Consistently well-reviewed in the style press.
Hush — a brand that understands how real women dress. Their shackets are relaxed, wearable, and sized thoughtfully. A great middle ground between high street and luxury.

Two Independent Brands I Keep Recommending

Rino & Pelle — a Dutch brand with a small but loyal following in the UK. Their shackets and overshirts are beautifully weighted, cut generously for layering, and made to last. Worth seeking out if you want something a little different.
Toast — quietly brilliant for considered, understated shackets in natural fabrics. Toast's sizing is relaxed and thoughtful, and their pieces age beautifully. Not cheap, but genuinely worth it.

Fit Tips by Body Shape

Petite frames: Look for shackets with a shorter back length (around 65–68cm) or shop petite-specific ranges. An oversized shacket on a petite frame can overwhelm — go for one that hits at the hip rather than mid-thigh.
Fuller bust: Prioritise chest measurement above everything else, and look for styles with button plackets that don't pull. Avoid very structured, boxy cuts — a slightly tapered body will be more flattering.
Broad shoulders: Check the shoulder measurement carefully. Fitted shackets in particular can pull across the back. A relaxed, unstructured fabric (like a soft flannel or cotton twill) will be more forgiving than a rigid canvas.
Tall frames: Look for styles with longer sleeves and a longer back length. ASOS Tall and Abercrombie are good starting points. Always check the actual sleeve length measurement rather than assuming a size L will be long enough.

The Shoulder Seam Check

Same rule applies here as with any structured top layer: the shoulder seam should sit right at the edge of your shoulder. If it's drooping down your upper arm, the shacket is too big in the shoulders — and unlike a chest that's slightly roomy (which you can layer into), a dropped shoulder seam will always look ill-fitting. It's the single quickest way to tell whether a shacket is actually your size.

Stop Guessing — Use Tellar

If all of this cross-referencing sounds exhausting, I completely understand. It is. That's exactly why Tellar.co.uk exists — it's the UK's leading free sizing tool, covering 1,500+ brands, and it matches your exact measurements to the right size in any brand instantly. No more brand-hopping through size guides, no more guessing, no more returns.

Here's how simple it is:

Measure once — your bust, waist, and hips, or plug in a size that already fits you well in a brand you know.
Use the Store Size Lookup tool — get your precise size across hundreds of brands including Zara, Barbour, Anthropologie, All Saints, and more.
It's always free — no app, no sign-up faff. Works straight in your browser.

If you want to get properly clued up on sizing across all your wardrobe staples, Tellar's Ultimate Clothing Sizing Guide is genuinely the best free resource out there — it covers everything from knitwear to dresses to outerwear in brilliant detail.

And if you're thinking about shackets as part of your outerwear layering strategy, it's worth reading the Ultimate Guide to Jackets on the Tellar Fashion Hub — it covers exactly how to layer and size outer layers for different body shapes and occasions.

The Tellar Fashion Hub is packed with honest, unsponsored styling advice across every fashion topic you can think of. No ads, no brand deals — just real, useful content from stylists who actually know what they're talking about. Well worth a browse.

Written by Ella Blake, Tellar Stylist