What Is Sizing Like at Reiss?

By Ella Blake — Fashion Stylist | Tellar Fashion Hub — Always honest, unbiased & unsponsored

Reiss runs true to size overall, but with a notably slim, tailored cut — particularly in their blazers, structured dresses and tailored trousers. If you carry any volume in the shoulders, bust or hips, or if you simply prefer your clothes not to feel sculpted to your exact outline, sizing up by one is a genuinely sensible move here. This is a brand built around a lean, clean silhouette, and the fit reflects that very deliberately.

I've recommended Reiss to clients for years — it sits in that sweet spot between proper high street and genuine luxury, and for workwear and smart occasionwear, it really is hard to beat at the price point. That said, I've also had to deliver the slightly awkward news more than once that yes, the blazer does fit — it's just cut for a narrower frame than my client actually has, and going up a size is not a failure, it's just how this brand works. Reiss designs for a specific silhouette. Know that going in and you'll have a much better experience.

About Reiss

Reiss was founded in 1971 and has been quietly building one of the most consistent and reliable identities in British fashion ever since. It occupies that coveted premium high street position — a step above Zara and Mango in quality and construction, but without the eye-watering price tags of full designer. Their aesthetic is clean, architectural and thoroughly grown-up: tailored suits, structured midi dresses, polished knitwear, sharp coats and the kind of wardrobe basics that actually look expensive rather than just claiming to be.

The brand became genuinely famous after the Duchess of Cambridge (now Princess of Wales) was photographed wearing their pieces repeatedly — which tells you everything about the market they're pitching to. This is dressing for women who want to look impeccably put-together without resorting to logos or obvious trends. It's a wardrobe investment brand, and the quality genuinely justifies the price for the pieces that work for you.

Reiss Size Guide

Reiss stocks UK sizes 4 through to 18 across most of their women's range. Here's how their sizing maps across regions — note that because of the brand's slim, tailored cut, many women find they need to reference the measurements rather than just the label size:

UK SizeEUUSBust (cm)Waist (cm)Hips (cm)UK 432076–7958–6184–87UK 634280–8362–6588–91UK 836484–8766–6992–95UK 1038688–9170–7396–99UK 1240892–9574–77100–103UK 14421096–9978–81104–107UK 164412100–10482–86108–112UK 184614105–10987–91113–117

Stylist note: Reiss sizing is consistent in terms of the label — a UK 12 is a UK 12 across most of their range. The issue is that the cut is slim. Always measure your bust, waist and hips before ordering and cross-reference against the measurements above rather than relying on what size you wear elsewhere.

Fit by Garment Type — What You Really Need to Know

Reiss does several things brilliantly, and a few things that require more careful sizing navigation. Here's the honest breakdown:

Blazers & tailored jackets: This is where Reiss really excels — and also where the slim cut is most pronounced. Their blazers are cut close through the shoulder and chest. If you have broader shoulders or a larger bust, size up. A Reiss blazer in the right size is genuinely one of the best things you can own; in the wrong size, it's just uncomfortable. I always say: the shoulder seam must sit exactly at the edge of your shoulder. If it pulls back, size up immediately.
Tailored trousers: Cut slim through the hip and thigh. True to size if you're a standard hourglass or straight shape, but if you carry more volume in the hip or thigh, go up one. Their wide-leg styles are more forgiving; the straight and slim cuts are not. Hemming is sometimes needed if you're under 5'6" as the legs tend to run long.
Structured dresses: Reiss dresses are some of their most popular pieces — and rightly so. Their midi dresses in particular are beautifully cut and photograph brilliantly. Sizing is true to size for most body shapes, but if you're fuller-busted (DD+), you may find the bodice pulls across the chest. Size up and have the waist taken in if needed — it's worth it for how good these dresses look.
Knitwear: One of the brand's most reliable categories for sizing. True to size with a relaxed, comfortable fit. Their knitwear is excellent quality and the sizing is consistently accurate. No drama here.
Coats & outerwear: True to size with a clean, uncluttered cut that layers well over tailoring. If you have broader shoulders or plan to wear thick layers underneath, go up one. Their coats are cut to sit sleek rather than generous, which is exactly the right aesthetic call — but it does mean layering space is limited at your standard size.
Going-out & occasion dresses: Reiss has expanded this category significantly in recent years and it's brilliant. Their satin and crepe occasion dresses tend to be true to size with a bit more give than their structured tailoring. Still worth checking the measurements if you're between sizes — but generally more forgiving than the tailored pieces.

My Honest Sizing Tips for Reiss

Measure before you order. More than almost any other brand at this price point, Reiss rewards knowing your actual measurements. The cut is precise enough that even a centimetre or two makes a visible difference in how a piece sits.
If you're between sizes, go up. The cut is slim enough that sizing up and having something taken in — especially on tailoring — is a far better outcome than buying too small and having nowhere to go.
Prioritise the shoulder on blazers. The shoulder seam is the thing you cannot fix without expensive alterations. Get that right and everything else can be adjusted.
Check whether the piece is lined. Reiss's lined pieces (most tailoring and occasion dresses) are more structured and less forgiving than their unlined jersey or knitwear styles. Lined pieces are where sizing accuracy matters most.
Use the in-store experience if you can. Reiss has excellent shop staff and the stores are genuinely worth visiting. Trying pieces in person before ordering online will save you a lot of uncertainty — especially with tailoring.

Love the Reiss Aesthetic? Here's Where Else to Shop

Reiss occupies a very specific niche — polished, minimal, investment-led — and there are some brilliant alternatives at every price point if the brand's sizing isn't working for you, or if you want to explore the same aesthetic with more range:

High Street & Accessible:

Whistles — Reiss's closest equivalent on the accessible premium high street. Beautifully cut tailoring, excellent occasion dressing, and a clean, considered aesthetic that doesn't chase trends. Sizing is generally more generous through the shoulder and bust.
Jigsaw — A brand that deserves far more attention than it gets. Quietly brilliant tailoring, beautiful fabrics, and a sizing that tends to be slightly more generous and forgiving than Reiss. Their coats and tailored dresses are exceptional.
COS — For a more architectural, minimal take on the Reiss aesthetic at a lower price. COS's structural pieces are a natural companion to Reiss's clean tailoring, and their sizing is generally reliable and consistent.
Massimo Dutti — The Zara group's premium label and a natural sister brand to Reiss in terms of aesthetic. Beautiful fabrication, understated tailoring and consistently reliable sizing. Often overlooked and absolutely shouldn't be.
Me&Em — An increasingly beloved British brand that occupies exactly the same considered, quality-focused space as Reiss. Their blazers and tailored trousers are exceptional and the sizing tends to be slightly more accommodating through the chest and hip.
LK Bennett — The brand for Reiss-adjacent dressing with a slightly more feminine, classic edge. Excellent for workwear, occasionwear and smart tailoring. Their fit is consistently accurate and slightly more generous than Reiss.
Hobbs — Beautifully made British tailoring and occasionwear. A slightly more classic sensibility than Reiss but the same commitment to quality and proper construction. Particularly strong for coats and occasion dresses.
Mint Velvet — Sits in the same price bracket as Reiss with a warmer, more relaxed take on polished dressing. Great for those who want the Reiss quality level but find the cut too restrictive.

Premium Step-Up:

Claudie Pierlot — The French premium brand that brings a touch of Parisian ease to exactly the kind of polished separates and dresses that Reiss does so well. Impeccably cut, beautifully detailed, and the sizing — while Parisian in cut — is worth navigating for the quality.
Hush — A quieter, more relaxed take on premium dressing. Excellent fabrics, beautiful knitwear and occasion pieces, and a noticeably more generous fit than Reiss. Brilliant for those who love the quality but not the slim cut.

Two Independent Labels Worth Discovering:

Ro&Zo — An independent British womenswear brand that consistently delivers beautifully cut occasion and workwear pieces at very competitive prices. Their tailoring and midi dresses sit in the same visual territory as Reiss but with a slightly more inclusive approach to fit — and they're frequently highlighted in Stylist and Grazia for exactly that reason. A genuinely brilliant find if you haven't come across them yet.
Finery London — Another independent UK label that punches well above its weight for polished, minimal dressing. Think elegant midi dresses, well-cut blazers and elevated basics with the kind of restrained aesthetic that Reiss has made its signature. Sizing is consistent and a little more generous through the body than Reiss — worth bookmarking immediately.

Get Your Exact Reiss Size — Instantly, Free, at Tellar

When a brand cuts as precisely as Reiss does, getting your size right before you order isn't just helpful — it's essential. That's exactly what Tellar.co.uk is built for.

Tellar is the UK's leading clothing sizing tool — completely free, no downloads, no subscriptions needed. Measure yourself once (bust, waist, hips — or just enter a brand size you already know fits), and Tellar instantly tells you your correct size across 1,500+ brands. Whether you're navigating Reiss's slim tailored cut or sizing across the brands in this post, it takes the guesswork out entirely.

✔ Free — always, works entirely in your browser
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And while you're there, explore the Tellar Fashion Hub — a library of free, unsponsored style posts covering sizing guides, brand breakdowns, trend edits and honest shopping advice. Written by real stylists. Never influenced by brand money.

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