How to Find Your Size in BA&SH

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

BA&SH runs in French sizing, which typically comes up one to two sizes smaller than standard UK sizing — so if you're a UK 10, you'll almost certainly be ordering a French 40, not a 38. Getting this wrong is by far the most common mistake shoppers make with the brand, and it explains a lot of the "it didn't fit at all" reviews you'll see online. Once you crack the conversion, though, BA&SH is one of the most reliable brands to shop online — the sizing is consistent and the quality genuinely lives up to the Parisian hype.

A Bit About BA&SH — And Why the Fit Is So Specific

Founded in Paris in 2003 by Barbara Boccara and Shah Dorani (the BA and SH of the name), the brand has become something of a shorthand for effortless French dressing. Think fluid midi skirts, beautifully cut blouses, the kind of blazer that looks like you threw it on and somehow ended up looking polished. It's a brand I genuinely love recommending to clients because it threads the needle between dressed-up and thrown-together better than almost anything else on the market at that price point.

But — and it's a fairly significant but — the brand cuts to a French body template. French women, as a general rule, tend to have a narrower frame through the shoulders and bust than the UK average. BA&SH doesn't compensate for this in the way that some European brands do. The result is beautiful clothes that fit French bodies brilliantly, and clothes that require a little extra thought for everyone else.

French Sizing vs UK Sizing — The Conversion You Need

Here's the straightforward conversion table. Bookmark this, screenshot it, do whatever you need to do — it will save you at least one annoying return:

BA&SH (FR Size)UK SizeBust (inches)Waist (inches)Hips (inches)34632"24"34"36834"26"36"381036"28"38"401238"30"40"421440"32"42"441642"34"44"

Ella's honest take: I ordered a BA&SH blouse in a French 38 — my standard European 10 — for a work trip to Paris. It fitted through the waist beautifully but was genuinely straining at the bust buttons. I'm a 36C, which is fairly average for the UK, and it was enough to cause a problem. I now automatically go up one in BA&SH tops and dresses unless the style is visibly oversized or has adjustable detailing. Life's too short for gaping buttons.

The Key Fit Rules by Category

BA&SH isn't a one-rule-fits-all brand. Here's how sizing plays out across different types of pieces:

Dresses and blouses: Always size for your bust first. If you have more than a B cup, go up one from your standard conversion. The cuts are often beautifully fluid below the waist, so a slightly larger size won't look baggy — it'll just hang properly.
Trousers and skirts: Slightly more forgiving. Size for your hips and — if you have a defined waist — a good tailor can take in the waistband for under £20. BA&SH trousers are worth the extra effort; they fall beautifully.
Blazers and jackets: Size for the shoulder, always. The shoulder seam must sit at your shoulder point — too wide and the whole silhouette collapses. BA&SH blazers are structured and unforgiving on a dropped shoulder. If you're between sizes, a tailor can adjust the body; they cannot easily adjust a shoulder.
Knitwear: BA&SH knitwear tends to have more ease than their tailored pieces. Stick to your standard conversion and you'll be fine. Fine-knit styles can be sized down if you prefer a closer fit.

What If I'm Between Sizes?

This comes up a lot with BA&SH, particularly for women who are a UK 12–14 or carry their weight differently on top vs bottom. My advice is always to size for the part of your body that's hardest to adjust. For most people, that means the bust and shoulders. A waist can be taken in; a bust seam is a much bigger job.

If you're a UK 10 on top and a 12 on the bottom, order the 40 (UK 12) across dresses and check whether the style has any waist definition built in — wrap styles, tie belts, and elasticated waists are your friends here, and BA&SH does all of them well.

How to Measure Yourself Properly

French sizing is only useful if you know your actual measurements — not the size on a UK label you've been wearing for years. Take two minutes to do this properly:

Bust: Measure around the fullest part of your chest, tape horizontal, arms relaxed at your sides. Wear your usual bra.
Waist: Natural waist — usually about an inch above your belly button at the narrowest point. Don't hold your breath.
Hips: Around the fullest part of your seat and hips, usually 8–9 inches below your natural waist.

Then cross-reference with the table above. If your measurements span two sizes, use the guidance above to decide which to prioritise based on the garment type.

Similar Brands Worth Shopping If You Love the BA&SH Aesthetic

If you're still working out your BA&SH size — or want more options at different price points — these brands share that same Parisian, feminine-but-undone sensibility:

MangoClaudie PierlotAnthropologieTed BakerFrench ConnectionZaraMint VelvetAll Saints

Mango — the closest high street match to BA&SH's Parisian aesthetic, at a fraction of the price. Their blouses and midi skirts in particular channel the same easy-elegant energy. Sizing is Spanish and also runs a touch small, so apply similar rules.
Claudie Pierlot — a direct Parisian rival and honestly a brilliant alternative. Slightly more structured than BA&SH, with similar French sizing. If you've cracked your BA&SH size, it'll map across almost perfectly.
Anthropologie — a brilliant option if you love the romantic, feminine feel of BA&SH but want more accessible sizing (Anthropologie uses standard UK sizes and is notably more inclusive in its cuts). Their brand IRO and Maeve lines in particular are worth a look.
Ted Baker — particularly strong for occasion pieces. Ted runs in its own numerical sizing (0–5) but the quality of the cut is genuinely comparable to BA&SH for dresses and blouses.
French Connection — reliable, wearable, and significantly more budget-friendly. The brand has quietly improved its quality in recent years and is a solid choice for BA&SH-adjacent pieces.
Zara — always worth a look for trend-led Parisian pieces, especially at the start of a new season. Sizing varies wildly by cut, so always check the specific item's measurements online before ordering.
Mint Velvet — particularly good if you're a UK 12–16 and find BA&SH's narrower cuts frustrating. Similar aesthetic, more relaxed fit, and honestly excellent quality for the price.
All Saints — for the edgier, more Parisian-rock side of BA&SH. Different vibe but the same devotion to beautifully draped, considered pieces. Sizing is UK standard and very consistent.

Two Independent Picks You Should Know About

Sézane — the Parisian independent that BA&SH is often compared to, and rightly so. Sézane has an even stronger commitment to quality and the pieces are genuinely timeless. French sizing applies here too, so use your BA&SH knowledge directly. Their knitwear and blouses are particularly outstanding.
Never Fully Dressed — a London-based independent label with a cult following and a wonderful approach to bold prints and feminine silhouettes. UK sizing, refreshingly inclusive size range, and the kind of pieces that get stopped on the street. Completely different price point to BA&SH but a brilliant complement to the wardrobe.

Stop Guessing. Let Tellar Do the Maths.

French sizing conversions, varying cuts, sizing up for the bust — it can feel like a lot. That's exactly why Tellar.co.uk exists. It's the UK's leading free sizing tool, and it takes all of this guesswork entirely off your plate.

Here's how it works:

Measure once — just your bust, waist, and hip measurements (or input a size you already know fits you well in another brand).
Use the Store Size Lookup tool to instantly get your exact size across 1,500+ brands — including BA&SH, Mango, Claudie Pierlot, and hundreds more.
Completely free — no app download, no subscription, no catch. It works in your browser right now.

And when you're done, explore the Tellar Fashion Hub — a library of honest, unsponsored style guides written by stylists with no brand deals and no agenda. Just straight answers.

Find My BA&SH Size Now →