Which Brands Have Sizing That's Consistent Across Their Whole Range?

The most consistent brands are the ones that design in-house from a single fit block and manufacture with a small group of factories — Uniqlo, COS, Boden, M&S, Massimo Dutti, Sweaty Betty and Me&Em are the reliable names in the UK. Brands that buy from dozens of suppliers, or sell third-party labels under their own size tag, are the ones that leave you with three different size 12s in the same wardrobe.

Why some brands are consistent and others simply can't be

It comes down to something unglamorous: the fit block. A brand builds one master pattern, fits it on one house model, and grades every size up and down from that. If they stick to it, a 12 is a 12 whether it's a blazer or a jersey dress.

The brands that drift are usually doing one of three things:

Sourcing widely. Fifty suppliers means fifty interpretations of the same measurements.
Running diffusion lines. Separate design teams, separate blocks, same label on the neck.
Reselling other brands. The size tag says the retailer's name, but the pattern belongs to somebody else entirely.

I learnt this the expensive way. Years ago I bought a beautiful wool coat from a retailer I won't name in a 12, went back a fortnight later for the same coat in a different colourway, and it didn't fasten. Same season, same style code, different factory. That coat still lives in the back of my wardrobe as a reminder.

High street brands you can genuinely trust

Uniqlo — the most standardised sizing on the high street, full stop. A medium tee, a medium shirt and a medium knit will all sit the same way on you, and their fabric behaviour barely shifts season to season.
COS — one clean block used right across the range. It's cut generously, so plenty of people take a size down, but the relationship between sizes never moves. Learn your COS size once and you're set.
M&S — an enormous fit-testing operation sits behind the scenes here. There's mild drift between sub-lines like Autograph and Collection, but core sizing holds better than almost any UK retailer of that scale.
Boden — famously stable year on year, which is exactly why secondhand Boden holds its value. Buyers on resale sites trust the numbers.
Massimo Dutti — excellent consistency, with one caveat worth knowing: tailoring runs noticeably slimmer than the knitwear. Within each category it's rock solid.
Whistles — dependable across dresses, knits and separates, with a slightly narrow shoulder that stays narrow no matter what you're buying.
Seasalt Cornwall — designed in-house in Falmouth with a relaxed block they've stuck with for years. Consistently roomy, which is different from being unpredictable.

Premium brands with reliable grading

Me&Em — consistent throughout, and consistently cut long. That's a deliberate design decision for taller women rather than sloppy grading, so once you've adjusted your expectations it's dependable.
Sweaty Betty — activewear demands precision because a badly graded legging is unwearable. Their sizing is tested hard and it shows.
Toast — relaxed, generous and completely predictable. A small is a small across every category they make.
Sézane — internally consistent, just small across the board compared to UK sizing. Once you know your Sézane size, it holds firm across shirts, knits and denim.

Luxury and designer

Toteme — tight, disciplined pattern-cutting from a small in-house team. Oversized by intention, never by accident.
Max Mara — decades of tailoring heritage and it shows in the grading. Their coat sizing is arguably the most reliable in the luxury market.
Joseph — an unusually stable block for a designer label, particularly across trousers and knitwear.

Two independents worth knowing

Community Clothing — Patrick Grant's label, made in British and Portuguese factories with deliberately standardised sizing as part of the pitch. Genuinely one of the most consistent things you can buy in the UK, and the price point is honest.
Palava — a small Bristol studio working from their own block with hand-drawn prints. Because everything comes from one pattern and one factory, the fit is identical whether you're buying a tea dress or a shirt.

The brands that will catch you out

For balance — Zara, ASOS own-label, Anthropologie and Free People all vary considerably, usually for the reasons above. Anthropologie in particular sells many third-party brands under one size label, so a 12 there is really a dozen different 12s. It's not a criticism of the clothes, just something to plan for.

My 30-second consistency test

Check whether the brand designs in-house or curates other labels.
Look at whether they publish one size guide or several by category.
Read the reviews on a knit and a pair of trousers. If both say "true to size", the block is holding.

How Tellar takes the guesswork out of it

This is exactly the problem I built Tellar to solve. It's the UK's leading sizing tool — your body matched precisely to over 1,500 brands instantly, so you never have to squint at a size guide again.

Measure once using your bust, waist and hip — or just tell us a brand size you already own.
Use the Store Size Lookup tool to get your exact size in any brand, including COS, Reiss, Arket and hundreds more.
Always free, no downloads, works straight in your browser.

There's also the Tellar Fashion Hub — a library stacked with free posts from our stylists. Honest, unbiased, independent and always free.

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