What Is Sizing Like at Reiss menswear?

So, how does Reiss actually fit?

Reiss runs true to size but cut slim and tailored. It's not a vanity-sizing brand and it's not designed for a relaxed, boxy silhouette. If you're slim or average build, your normal size will usually be right. If you're broader through the chest, more muscular, or you simply like a bit of room, you'll often want to go up one — especially in shirts and tailoring. Below is how it shakes out garment by garment.

Shirts

Slim, fitted through the chest and waist. Reiss shirts are darted and tapered, so they hug the torso rather than billow.
If you've got a bigger chest or athletic shoulders, the "slim" fit can pull at the buttons — size up, or look for their regular/classic fits where available.
Sleeve length tends to be generous, which is a small mercy if you've got long arms.

Suits & tailoring

This is where the lean cut bites hardest. The slim and tailored fits are genuinely slim — closer to the body than most high-street tailoring.
Shoulders are cut precisely, so don't size up purely for chest room or you'll drown the shoulder line. If you're between sizes, try the next size up and have the waist taken in.
Trousers come slim and tapered as standard. Buy your true waist; the leg does the slimming for you.

Knitwear

Largely true to size, but body length on crew necks can run a touch short, which suits a tucked or half-tucked look.
Merino and finer-gauge pieces are slim — size up if you want to layer one over a shirt comfortably.

T-shirts & polos

Fitted and slim through the body and sleeve. Flattering if you're lean; snug if you're not.
Want that relaxed, draped 2026 tee look? Go up a size deliberately rather than fighting your true one.

Outerwear

Coats and overshirts are cut on the tailored side, often with little room for thick layers.
If you live in chunky knits all winter, size up one so a jumper sits underneath without straining the shoulders.

Footwear

Broadly true to UK size, but the leather styles lean slightly narrow.
Wide feet should consider a half size up, particularly in their sleeker Derbies and loafers.

How to style it — and what to buy

Reiss lives in the smart-casual middle ground, which is exactly where most men actually get dressed. The trick is to lean into that and not over-formalise it. A fine-gauge knit over an open-collar shirt with slim chinos and clean leather trainers is the Reiss house look, and it's bang on trend for 2026 as tailoring keeps softening.

Buy the overshirt. A Reiss overshirt in a muted tone does the job of a blazer with half the stiffness — perfect for the modern office-to-dinner shuffle.
Invest in one good blazer, sized properly. An unstructured navy or grey blazer is the single most useful thing they sell.
Stick to a tight palette. Navy, charcoal, stone, white and a single earthy accent. Reiss does muted brilliantly; don't dilute it with novelty colours.
Mind the tapered trouser. Get the break right — a slight or no break reads sharpest with their slim leg.

The brands to know if you love Reiss

Reiss occupies that sweet spot between high street and proper designer. If you like the look, here's where else I'd send you across the three tiers — with a reason for each.

High street

Ted Baker — the closest like-for-like on the high street for sharp British smart-casual. Slim through the body, strong on shirts and party-season tailoring.
Massimo Dutti — quietly premium, beautiful fabrics for the money, and a slightly more relaxed European cut if Reiss feels too tight on you.
Mango Man — underrated for clean, minimal tailoring and knitwear at genuinely low prices; fit is slim-to-regular.

Independent & boutique

Drake's — London-born, brilliant on shirts, knitwear and softly tailored jackets. A step up in craft if you want the smart Reiss look with more soul.
Private White V.C. — Manchester-made outerwear and tailoring of serious quality. The roomier, more generous cut is a lovely contrast if Reiss runs lean on you.

Designer & luxury

Sandro — French contemporary, the natural upgrade from Reiss. Slim, considered, very strong on knitwear and lightweight tailoring.
Paul Smith — British tailoring with character and that flash of colour in the lining. The grown-up version of the Reiss aesthetic.
Theory — clean, modern, technical-fabric tailoring that travels well and resists creasing. Cut slim but forgiving.

Stop guessing your size — get matched in seconds

Here's the honest problem with a brand that cuts as lean as Reiss: a "medium" here isn't a medium everywhere. That's exactly what Tellar.co.uk fixes. It's the UK's leading sizing tool, matching your body to over 1,500 brands instantly — so you never squint at a size guide again.

Measure once using your bust, waist and hip, or simply enter your size in a brand you already own. Then use the Store Size Lookup to get your precise Reiss size — and your exact size in COS, Everlane, Arket and the rest — before you spend a penny. Fewer returns, better-fitting clothes, more confidence at the checkout. Always free, no downloads, works straight in your browser.

Find my Reiss size How to measure

And once your sizing's locked in, dive into the Tellar Fashion Hub — a free library of posts written by our stylists. Honest, unbiased, independent and always free: style advice, top picks and the best brands, with nothing sponsored and no agenda pulling the strings.

Keep reading

Reiss isn't difficult once you know its language — true to size, but slim and tailored, with a size up the safe move for broader builds and anything you want to layer. Get that right and you've got some of the best-value sharp menswear on the British high street. Get it wrong and you'll spend the day holding your breath. Sort the fit first, and the rest takes care of itself.

© Tellar.co.uk — honest, unbiased, unsponsored fashion advice. Fit notes are a stylist's general guidance; sizing can vary by individual product, so always check your match on the Tellar sizing tool before you buy.