How to Find Your Size in B Sides

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

B Sides runs true to size on the waist but cut slim through the hip and thigh — if you're not a straight-up slim build, sizing up one is the smartest move you'll make. This is a cult American denim label beloved by the fashion industry's most discerning denim heads, and the fit is very much designed with a lean, narrow silhouette in mind. But don't let that put you off — once you crack the sizing, B Sides jeans are genuinely among the best you'll ever wear.

What Is B Sides?

If you're not already in the B Sides universe, let me bring you up to speed. B Sides is a New York-founded premium denim label that has quietly built one of the most devoted cult followings in the industry. They work exclusively with Japanese and Italian selvedge denim — the good stuff — and each style has a slightly different vintage wash, cut, and character. These aren't jeans you buy in bulk. You find your pair, you wear them into the ground, and you become completely evangelical about them to everyone you know. I speak from personal experience.

I came across B Sides through a stylist friend who wore a pair of their Lasso straight-leg jeans to a shoot. They looked so perfectly broken-in and effortless — that brilliant sweet spot between vintage and intentional — that I immediately asked about them. She looked at me like I'd asked who invented water. "B Sides, obviously." Obviously.

How Does B Sides Size Up?

Right, here's the practical bit. B Sides uses US waist sizing (24, 25, 26, 27, 28, 29, 30, 31, 32), which is fairly standard for premium denim, but the cut is where things get more nuanced:

Waist sizing is accurate — you can generally go with your usual waist measurement here without too much drama
The hip and thigh run slim — this is the real catch; if you carry any volume through the hip or thigh, size up at least one, possibly two
Stretch content varies by style — some B Sides jeans are rigid selvedge with zero stretch; others have a small percentage of elastane. Always check before you buy
Rigid denim will stretch out by about half a size after a few wears, so don't panic if they feel tight in the first week — that's normal and expected with selvedge
Leg length runs long — B Sides is made with an American frame in mind; if you're under 5'6" you'll almost certainly need to hem

The B Sides Size Chart in Brief

As a rough guide for UK women:

US 26 ≈ UK 8
US 27 ≈ UK 10
US 28 ≈ UK 10–12
US 29 ≈ UK 12
US 30 ≈ UK 12–14
US 31 ≈ UK 14

These are starting points — your actual size will depend on which B Sides style you're buying and your own proportions. Always measure your waist and hips, then cross-reference with the specific style's measurements on the product page.

Which B Sides Styles Should You Know About?

B Sides has a few signature cuts worth understanding before you shop:

The Lasso: Their most popular style — a slim straight leg with a mid-rise. This is the one that converts people. Size up if you're hip-heavy
The Pleated Lasso: A wider, more relaxed version with a subtle pleat at the waist — this gives you a bit more room through the hip and thigh, making it a great option if the original Lasso feels too snug
The Slim: Does exactly what it says — very slim through the leg. For narrow frames or those who love a skinny fit, this is your style. Everyone else: size up
Flared styles: B Sides do the occasional flare cut, and these are the most forgiving in terms of hip and thigh room. If sizing has been your sticking point, start here

My Top Tips for Getting the Right B Sides Fit

Measure your hips first, not just your waist. The hip measurement is your true guide with this brand
Buy rigid denim slightly snug — it will ease out. Buy it already uncomfortable and you'll be miserable
Budget for a hem. Seriously, factor this in. A good tailor's hem on a pair of selvedge jeans costs about £15–£20 and makes the world of difference
Look at the inseam measurement on the product page, not just the waist size — it'll tell you a lot about whether you need to adjust for height
Read the fabric composition. If it says 100% cotton, expect no stretch and size accordingly

Brands Worth Exploring Alongside B Sides

B Sides sits firmly in the premium-to-luxury denim space. Here's where I'd direct you depending on your budget and style:

High street & accessible options:

Levi's — still the benchmark for accessible selvedge-adjacent denim; the Levi's 501 is genuinely timeless and the sizing is well-documented and reliable
Mango — consistently excellent for straight-leg and wide-leg denim; great quality-to-price ratio and their sizing is honest
Abercrombie & Fitch — had a full denim renaissance and their Curve Love range in particular has earned serious praise; brilliant if B Sides' slim cut doesn't work for your shape
ASOS — a solid starting point for exploring different denim fits before committing to premium; their own-brand jeans have genuinely improved
Zara — strong on trend-led denim; good for the wide-leg and barrel-leg moment if you want to try the silhouette without the investment price tag

Premium & mid-market:

Citizens of Humanity — probably the closest comparison to B Sides in terms of premium quality, beautiful washes, and the same grown-up denim energy; slightly more size-inclusive through the hip
Paige — luxurious denim with excellent stretch options; if B Sides' rigid selvedge feels too unforgiving, Paige is where I'd send you next
Cos — brilliant for elevated basics including straight-cut denim with clean, architectural lines; sizing is consistent and reliable

Two independent brands worth knowing:

Ksubi — an Australian cult denim brand that deserves far more recognition in the UK. Their raw denim is extraordinary, the washes are unique, and the fit has a similar slim-but-considered quality to B Sides. If you love B Sides, Ksubi is your next stop
Boyish Jeans — a sustainable, California-founded denim label making beautiful vintage-inspired styles from recycled fabrics. Genuinely excellent quality, thoughtful sizing information, and a strong ethical story. Worn by people who care about what their jeans are actually made from

Take the Guesswork Out of Denim Sizing — Use Tellar

Premium denim sizing is notoriously inconsistent across brands, and B Sides is no exception. If you want to shop with real confidence — across B Sides, Citizens of Humanity, Paige, Levi's, and 1,500+ other brands — Tellar.co.uk is your answer. It's the UK's leading free sizing tool and it genuinely removes the guesswork entirely.

Here's how it works:

Step 1 — Measure once: Enter your bust, waist, and hip measurements — or simply your existing size in a brand that already fits you well
Step 2 — Use the Store Size Lookup tool: Get your precise recommended size across 1,500+ brands instantly — no size chart squinting, no guessing
Step 3 — Shop with confidence: Entirely free, works in-browser, no downloads or sign-up required

Tellar also runs a Fashion Hub — a library of honest, unsponsored style guides written by real stylists. No ads, no brand deals, no sponsored fluff. Just straight-talking fashion advice you can actually use.

More reads from the Tellar Fashion Hub:

The Final Word on B Sides Sizing

B Sides is the kind of denim brand that, once you've worn it, recalibrates your whole standard for what jeans should feel like. The craftsmanship is exceptional, the washes are beautiful, and the slim cut — once you've sized correctly — is genuinely flattering. Just go in with your hip measurement front and centre, account for the fact that rigid selvedge will ease out, and budget for a hem if you're on the shorter side. Do all of that and you're set. Welcome to the cult.

Written by Ella Blake for the Tellar Fashion Hub