What Is Vanity Sizing — And Why Does Your Size Mean Absolutely Nothing Any More?

SIZING & FIT

From a size 10 at one shop to a size 14 at the next — without changing shape. Here's what's really going on.

BY THE TELLAR STYLE TEAM  |  TELLAR FASHION HUB

Vanity sizing is when clothing brands deliberately label their garments with a smaller size number than the actual measurements would call for — essentially flattering you into feeling smaller than the tape measure would suggest, so you feel good about yourself and, crucially, about them. It's why you can walk into three different shops on the same afternoon, try on a completely different number in each, and leave thoroughly confused about your own body.

I remember doing exactly that. One Saturday, armed with what I thought was a perfectly clear understanding of my size, I came home with a pair of jeans labelled size 10, a blouse labelled size 14, and a jacket labelled size 12. Same body. Same day. I genuinely sat on the end of my bed and questioned everything. The answer, of course, wasn't me — it was vanity sizing, and it's been quietly wreaking havoc on our wardrobes for decades.

Why Do Brands Do This?

The short answer is psychology. Studies have consistently shown that shoppers are more likely to make a purchase — and to return to a brand — when the number on the label makes them feel good. If you squeeze into a size 8 after a difficult week, you're going to associate that warm, fuzzy feeling with that particular brand. It's calculated, it's clever, and it absolutely works. Brands know it. Retailers know it. And now, thankfully, so do you.

The knock-on effect is a total free-for-all on sizing standards. There is no single governing body dictating what a "size 12" should measure in the UK. Each brand operates to its own internal standards, which shift over time depending on their target customer, their market position, and honestly — whoever was in charge of their grading charts that season.

"A size label is just a number. It tells you almost nothing useful about whether a garment will actually fit your body."

The High Street: Who Runs Big, Who Runs Small

This is where it gets genuinely useful, so pay attention:

• Zara — Runs small, full stop. Their European cut means if you're between sizes, size up. Their denim in particular has a habit of being a full size smaller than you'd expect.

• H&M — Has been widely reported to run large for its labels, particularly in basics and jersey. A size 10 in H&M can genuinely be a 12 elsewhere. Great for your ego; maddening for consistency.

• ASOS — Completely inconsistent across its own-brand lines because they work with multiple manufacturers. Their branded pieces from other labels are more reliable, but ASOS Design? Go purely by the measurements.

• M&S — One of the more consistent high street retailers, and they deserve credit for it. Their Per Una and main line sizing is reasonably true to UK standard, though knitwear can vary.

• Next — Similarly reliable, particularly for basics. A solid benchmark brand if you want consistency.

• Mango — Runs small owing to its Spanish origins. If you're used to UK high street sizing, sizing up by one is a safe strategy across their tailoring and denim.

• COS — True-to-small, especially in their more structured pieces. Their oversized pieces are, of course, intentionally roomy — check the product description carefully to understand the intended fit.

• Whistles — Premium high street with more consistent sizing than most fast fashion. Worth knowing as a reliable benchmark in the mid-market space.

• Reiss — Tends to run true to size with a tailored, fitted cut. If you're between sizes in Reiss, size up — their cuts are precise and there's rarely extra room to play with.

Premium & Luxury — Does a Higher Price Mean Better Sizing?

Not necessarily, and this might be the most important thing I tell you today. Premium brands can actually be more inconsistent than the high street because they're catering to a very specific customer and cut accordingly.

Me&Em is a premium brand that genuinely gets sizing right — they're honest, their fit notes are detailed, and their sizing is consistent across collections. If you don't know Me&Em, you should.

At the luxury end, Max Mara is the classic example of a brand that sizes firmly on the smaller side. Their Italian heritage means the sizing philosophy is different — always try before you buy, or use your measurements. Going up a size at Max Mara is not a defeat; it's just pragmatism.

Two Independent Brands Worth Knowing

Kitri, the London-based indie label that's become a genuine favourite with fashion editors, does something genuinely brilliant: they include detailed fit notes on every single product page. They'll tell you if something runs small, if it's designed to be oversized, and what height and size the model is wearing. It sounds obvious, but it's still rare enough to feel radical.

Sézane, the French indie brand with a devoted following, sizes in European measurements and tends to run small-to-true. Their pieces are beautifully made and worth the investment — just size up by one as a general rule, particularly in their shirts and trousers.

Why Vanity Sizing Is About More Than Just Inconvenience

The real damage isn't the wasted time on returns, frustrating as that is. It's the way inconsistent sizing erodes our relationship with our own bodies. When a number means something different in every shop, we start attaching emotional significance to the number itself — feeling good when it's lower, deflated when it's higher. That's an exhausting and completely unnecessary way to interact with getting dressed.

The fix is simple in theory: stop using the number as your guide. Your measurements don't change because a brand decided to call a 32" waist a size 10. Your body doesn't change. The label is the problem, not you.

Stop Guessing. Start Knowing. Meet Tellar.

Tellar is the UK's leading sizing tool — and honestly, it's the thing I wish had existed ten years and approximately two hundred failed online orders ago. It matches your exact body measurements to 1,500+ brands instantly. Measure once — bust, waist, hips — or enter your known size in a brand you already trust, and Tellar tells you your precise size across every brand in their database. No size guides. No guesswork. No more returns because a size 12 wasn't a size 12.

It's completely free, works in-browser, and requires no download. Just honest, accurate sizing information — finally.

Use the Store Size Lookup tool to find your exact size in brands like COS, Reiss, Everlane, Arket, and over 1,500 more. Then explore the Tellar Fashion Hub — a growing library of free, unbiased style guides from real stylists. No sponsored content. No brand agendas. Just genuinely useful fashion advice, always free.

FIND MY SIZE →EXPLORE FASHION HUB →

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Tellar.co.uk  |  The UK's Leading Sizing Tool  |  Always Free. Always Unbiased. Always Honest.