What Is Sizing Like at Y/Project? A Stylist's Honest Guide

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

Y/Project runs small and narrow, sizing in European (EU) numbers that typically sit one to two sizes smaller than standard UK sizing — so if you are a UK 10, you will very likely need an EU 38, and potentially a 40 in more structured or body-skimming pieces.

That answer took me an embarrassing amount of time to learn the hard way. I once confidently ordered a pair of Y/Project straight-leg jeans in my usual EU 36 and they arrived looking — quite dramatically — like something designed for a child-sized mannequin. I swapped them out for a 38, which was still a snug fit. Lesson: size up, always, and never skip their size guide.

Y/Project is the Antwerp-born, Paris-based label founded by Glenn Martens (now with Diesel, though Jean-Charles de Castelbajac helms the creative direction today). It is known for architectural, deconstructed pieces — exaggerated silhouettes, layered waistbands, unexpected cutouts. Glorious, but unforgiving if you get the size wrong.

Y/Project Size Conversion Table

Use this as your starting guide. When in doubt, always measure your body and check against the brand's specific garment measurements rather than relying purely on your number.

My advice: add 2cm to your actual measurements before selecting a size. Y/Project's fits are intentionally precise and their fabrics — particularly the denim and structured jersey — have very little give in them.

Sizing Garment by Garment

Y/Project is not one of those brands where sizing is consistent across the board. Different categories behave very differently, so it is worth going garment by garment.

Jeans & Trousers: Run noticeably small and slim through the seat and thigh. Size up at least one, sometimes two EU sizes. The waistband construction — often exaggerated and double-layered — can also pull tighter than you expect. If you carry volume in your hips or thighs, size by hip measurement and have a tailor take in the waist if needed.
Knitwear & Tops: More forgiving than the bottoms, but still on the small side. Their knits can have an intentional oversized or asymmetric fit, so read the product description carefully — some are meant to look enormous, others are fitted by design. If it says "relaxed fit", true to size is generally fine. If it says "slim" or "fitted", go up.
Dresses: These vary enormously depending on the cut. Bias-cut and draped styles tend to be more lenient; structured mini dresses are extremely fitted at the bodice. I would always size up on dresses unless you are extremely slim-framed.
Outerwear & Jackets: Interestingly, the jackets and coats — particularly their belted trench and denim jacket styles — tend to run slightly more generously than other categories. True to size is often fine here if you are not layering heavily underneath. If you plan to wear over chunky knitwear, go up one.
Footwear: Y/Project shoes (their famous multi-strap sandals and boots) generally run true to European size. However, the ankle strap styles can feel narrow on wider feet, so bear that in mind.

What About Their Fabric & Construction?

Part of why sizing feels so exacting at Y/Project is the quality and specificity of their construction. They are not cutting garments with extra ease built in. The fabrics — whether it is their signature rigid denim, structured cotton poplin, or dense jersey — are chosen to hold the architectural shape the designers intend. There is no stretch to save you, no drape to forgive a size up. It is, frankly, a bit unforgiving — but that is also exactly what you are paying for. These pieces are precise, considered, and extraordinary when they fit properly.

Who Is Y/Project Best For?

Honestly? Y/Project rewards those who know their exact measurements and are comfortable sizing up for a good fit. If you are petite and slim-framed, you will likely find their proportions work beautifully — especially the knitwear and tailored pieces. If you have a fuller bust, wider hips, or are between sizes, I would strongly recommend buying from a retailer with a good returns policy and ordering two sizes to compare. Net-a-Porter and SSENSE both have fairly straightforward return processes.

Alternatives — From High Street to Luxury

Y/Project carries luxury price tags (expect £300–£1,200+ for key pieces). If you love the avant-garde, architectural aesthetic but want to explore across price points, here are my honest recommendations:

High Street & Mid-Market Picks:

Cos — Architectural minimalism that genuinely echoes the Y/Project aesthetic at a fraction of the price. Their structural tailoring and asymmetric knitwear are excellent.
Zara — Reliably picks up on avant-garde runway trends quickly. Look for their Studio and limited-edition ranges for the most interesting pieces.
Mango — Their premium Committed and Mango Essentials lines do clean, sculptural dressing well. Good denim too.
Whistles — British, precise, and thoughtfully cut. Not as experimental as Y/Project but excellent quality at a sensible price point.
All Saints — For the edgier, darker aesthetic that Y/Project fans often gravitate towards. Their leather and utility pieces are strong.
Anthropologie — Great for unique, expressive pieces with an independent feel. Their knitwear and dresses can have that unexpected design element that Y/Project does so well.
Urban Outfitters — A good source for directional, trend-led pieces inspired by the avant-garde scene, particularly for younger shoppers.
Massimo Dutti — Sophisticated and extremely well-cut. Great alternative for structured tailoring with a European sensibility.

Independent & Niche Picks:

Paloma Wool — A Barcelona-based label beloved by the fashion crowd. Artistic, expressive, brilliant knitwear and cut-out details. Affordable luxury and very much in the same creative spirit as Y/Project.
Baserange — A Copenhagen/Paris brand with a devoted following. Minimalist but deeply considered, excellent quality basics with a sculptural edge. Great for building an avant-garde wardrobe around.

Premium & Luxury Alternatives:

Jacquemus — Another French label with exaggerated proportions and precise tailoring. Similar sizing challenges, but equally rewarding when it fits.
Marni — Artistic, slightly offbeat, and beautifully constructed. Sizing runs more generously than Y/Project.
Acne Studios — Swedish minimalism with an edge. More accessible sizing and one of the best denim ranges at the luxury level.

Never Guess Your Size Again — Use Tellar

Y/Project's sizing quirks are exactly why Tellar.co.uk exists. It is the UK's leading free sizing tool — no downloads, no subscriptions, no faff.

Measure once — just your bust, waist, and hips (or use an existing brand size you trust)
Get your precise size in over 1,500 brands instantly using the Store Size Lookup tool
Always free — works in-browser, no account needed

Plus, explore the Tellar Fashion Hub — a library of free, honest, unsponsored style guides written by our team of stylists. No ads. No brand deals. Just straight advice.

👉 tellar.co.uk | Store Size Lookup Tool