What Is Sizing Like at Seventy + Mochi?

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

Seventy + Mochi runs broadly true to size, but the fit varies noticeably depending on whether you're shopping their denim jeans, relaxed jumpsuits, or more structured tops and waistcoats — so it pays to know the nuances before you click "add to basket."

I'll be honest: the first time I ordered from seventy + mochi, I went with my usual size in their wide-leg jeans and they were slightly roomier than I'd expected around the hip. The second time, I tried their button-front flare style and very nearly had a wardrobe disaster — they ran noticeably snugger in the waist and I was grateful I'd checked before a long day out. That taught me something: this is a brand where silhouette and fabric matter a lot more than just picking your standard size.

So let me walk you through it properly.

Who Is Seventy + Mochi?

If you haven't come across seventy + mochi yet, it's a premium sustainable denim label that's been quietly gaining a very loyal following. The brand is rooted in the idea of "consciously kind" fashion — their pieces are made with organic cotton, recycled fibres, hemp blends, and eco-made elastane. The aesthetic is effortlessly cool: wide-leg and barrel jeans, relaxed co-ords, denim jackets, and soft blouses, all with a nod to 70s-inspired silhouettes. It's the kind of brand that sits very comfortably alongside Ganni or Sézane in your wardrobe — elevated, considered, and very wearable.

Sizing runs from US 2 up to US 14 (UK 6–18), with denim also available in numeric waist sizes 24–32. From Spring 2025 onwards, seventy + mochi updated their sizing charts following a dedicated fit workshop and customer feedback process, so do bear in mind that older stock may have slightly different measurements.

Seventy + Mochi Size Conversion Chart

The brand uses US sizing, so here's how that translates for UK shoppers:

UK SizeUS SizeEU SizeBust (cm)Waist (cm)Hip (cm)62 / XS3478–8060–6285–8784 / S3681–8463–6688–91106 / M3885–8967–7192–96128 / M-L4090–9472–7697–1011410 / L4295–9977–81102–1061612 / XL44100–10582–87107–1121814 / XXL46106–11088–93113–117

For denim specifically, they also use numeric waist sizing (24–32). A UK 8 typically corresponds to a 26/27, a UK 10 to a 27/28, and a UK 12 to a 28/29 — though this can shift depending on stretch content and rise height.

Fit By Garment Type

This is where it gets interesting — and where knowing the specifics will save you a return.

Jeans (wide-leg & barrel): Generally true to size with a relaxed, roomy feel through the hip and thigh. If you're between sizes and prefer a cleaner line, size down.
Jeans (button-front flare & fitted rise styles): These tend to run slightly small in the waist. Size up if you're curvy or if the waistband is the part that usually catches you out. The Marie style in particular has been noted by multiple retailers as running snug — I'd size up on that one without hesitation.
Straight-leg & high-rise styles: True to size for most body types. Rigid denim (no stretch) will relax with wear, so expect them to soften over the first few wears.
Jumpsuits: Cut with a relaxed, boyish silhouette. True to size overall, but the brand advises sizing down if you want a more fitted look. Their fit model wears her true size for a laid-back feel.
Denim jackets & outerwear: Slightly generous — true to size if you want that effortless oversized finish, or size down for a more tailored look.
Vests & waistcoats: These have a more structured bodice and can run fitted through the bust and upper body. I'd recommend going up a size if you have a fuller bust.
Tops & blouses: True to size. Most styles are relaxed or slightly oversized by design, so there's less risk here.

A Note on Inseam & Length

The brand fits to a model who is 5'6" / 167cm, which is fairly average for UK women. Most styles are designed to sit at either full length, low ankle, or high ankle on that frame. The good news is that from their "Tailored to You" edit onwards, seventy + mochi now offer select styles in short and regular inseam options — brilliant news if you're petite or find most denim either swamps you or hits at the wrong point on the ankle.

My Honest Sizing Verdict

For most women, I'd say: go true to size as your starting point, then adjust based on rise and fabric. If you're between sizes and tend to carry weight through the hip or thigh, size up. If you're buying a button-front style or anything described as "high-rise fitted," I'd err on the side of a size up too — you can always belt it, and the fabric will soften beautifully with wear.

The quality of seventy + mochi denim is genuinely excellent. The organic cotton and hemp blends feel substantial without being stiff, and styles hold their shape far better than a lot of high street denim I've tested. This is not a brand where you'll be tugging at your waistband by lunchtime.

Similar Brands Worth Knowing

If seventy + mochi has caught your eye but you'd like to compare fit and price across a broader range, here's where I'd look:

High Street Picks:

Mango — Consistently one of the better high street denim options; their barrel and wide-leg styles in particular rival more premium brands on finish and fit.
Abercrombie & Fitch — Genuinely impressive jeans that have earned a massive following for their inclusive sizing and flattering cuts. If you've not tried them, they're worth a look.
Cos — Minimalist, considered design with a great range of relaxed and tailored denim. Very consistent sizing and lovely quality fabrics.
Levi — The original, and still brilliant. The 501 and Ribcage styles offer the same high-rise energy as seventy + mochi at a more accessible price point.
Massimo Dutti — Elevated high street denim with a polished edge. Think premium fabrics and a slightly more classic fit.
Zara — Their denim has genuinely improved. Great trend-led options that tap into similar wide-leg and barrel silhouettes.
Whistles — Understated British label with excellent-quality denim pieces that sit beautifully without trying too hard.

Premium Picks:

Citizens of Humanity — The closest premium denim comparison in terms of fabric quality and sustainable credentials. Excellent fit and a brand worth investing in.
Me&Em — A brilliant British brand for elevated denim and separates. Great fit across a wide range of body types, and the quality is exceptional.
Paige — Premium American denim brand with incredible stretch technology. If comfort is your priority alongside quality, Paige delivers every time.

Independent Finds:

E.L.V. Denim — A London-based label making jeans entirely from repurposed denim fabric. Beautifully crafted, genuinely sustainable, and each pair is essentially unique. A real find.
Boyish Jeans — A US-based label creating gorgeous sustainable denim with excellent size inclusivity and a similar ethos to seventy + mochi. Very well reviewed for fit and longevity.

Not Sure of Your Seventy + Mochi Size?

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