How Do I Find My Size in Jeans?

By Ella Blake, Tellar Stylist

Finding your size in jeans comes down to three measurements: your waist in inches, your hip measurement, and your inside leg length — once you have those, you can crack the code of any brand's sizing. I know that sounds almost too simple, but honestly, it's the one piece of advice I wish someone had given me years earlier. Before I worked in fashion, I spent an embarrassing amount of time in changing rooms wrestling with jeans that were perfect on the hanger and absolutely impossible on my body. Sound familiar?

The maddening truth is that jeans sizing is one of the least standardised areas of clothing. A size 12 in M&S is not the same as a size 12 in Levi's, which is not the same as a size 12 in Citizens of Humanity. Add in vanity sizing — where brands quietly adjust their measurements to flatter customers into buying — and it becomes a complete lottery.

Start With Your Measurements (Not a Guess)

The most important thing you can do before buying any pair of jeans is take three measurements:

Waist: Measure around the narrowest part of your natural waist — not where you wear your jeans, but your actual waist.
Hips: Measure around the fullest part of your hips, usually about 20–23cm below your waist.
Inside leg: From your crotch to your ankle bone. Get someone to help with this one if you can — it's almost impossible to do accurately on your own.

Write these down. Keep them on your phone. They're genuinely more useful than any size label.

Decoding Jean Sizing: UK vs US vs European

British high street brands like Next, Marks & Spencer, and White Stuff generally use UK dress sizing — so a size 10, 12, 14 and so on. Simple enough. The complication starts when you move into denim-specific brands.

American and denim-specialist brands like Levi's, Paige, and Citizens of Humanity use a waist measurement system — you'll see sizes listed as 26, 27, 28, 29, 30 and so on. These refer to your waist in inches. But — and this is the catch — they're rarely accurate. Most brands run at least an inch or two vanity-sized, meaning a "27" often measures closer to 29 inches in reality. The only way to navigate this confidently is to know your actual measurements and check them against each brand's specific size guide.

European sizing adds another layer. Brands like Mango and Massimo Dutti use EU sizing (36, 38, 40 etc.). If you're shopping Cos — which runs notoriously small — I'd always recommend sizing up one from your usual EU size, particularly if you're curvy through the hip or thigh.

The Rise Question: It Changes Everything

One thing that catches people out constantly is rise — the distance from the crotch seam to the waistband. This affects both fit and how flattering a jean looks on you, and it's not something that gets talked about enough.

Low rise: Sits several inches below your natural waist. Great if you have a shorter torso; can be tricky if you have a fuller tummy or hips.
Mid rise: The most universally flattering — sits just below the belly button and works on most body shapes.
High rise: Sits at or above the natural waist. Brilliant for elongating the legs, defining the waist, and smoothing the tummy area.

I'm naturally petite with a shorter inside leg, and for years I wrote off wide-leg jeans as "not for me." Then I tried a high-rise, wide-leg pair from Abercrombie & Fitch — which have a brilliant petite range — hemmed them up about two inches, and honestly? Changed my life. Never say never with jeans.

Best High Street Brands for Jeans — By Fit

Not all high street stores are created equal when it comes to denim. Here's what I genuinely recommend, based on experience and what's getting excellent press right now:

Abercrombie & Fitch — Their Curve Love range is a brilliant option if you carry more through the hip and thigh than the waist. The fit engineering is genuinely impressive.
Mango — Excellent for trend-led styles at a fair price. Their straight and barrel-leg jeans have been consistently well-reviewed and they size pretty true to label.
Reiss — A step up in quality from the high street, and their denim is particularly good for a clean, tailored finish. Worth it for a classic slim or straight leg.
Topshop (via ASOS) — The Jamie and Editor styles remain cult classics with good reason. Great for hourglass figures.
Whistles — Beautifully cut and made from quality denim. Their straight-leg styles are particularly wearable and won't date.
River Island — Excellent for curvier shapes with their mid-rise and high-rise fits. Great value too.
Boden — Slightly under-the-radar for denim, but their slim and straight cuts are reliable, especially if you're after a more classic look rather than trend pieces.

Two Independent Brands Worth Knowing

If you want to move away from the mainstream, I'd point you towards Outland Denim — an ethical, size-inclusive Australian brand with a European following that does gorgeous mid-rise straight and slim cuts, and ships to the UK. Their sizing is clear and consistent, and they're brilliant for those wanting to buy more consciously.

For premium, smaller-run denim, Boyish Jeans is worth a look — a sustainable LA brand with a dedicated UK following. Their high-waisted styles are incredibly flattering and made from organic or recycled fabrics. Neither brand will let you down, and it's always nice to wear something that isn't on every other person on the street.

A Few Practical Rules I Live By

Never buy jeans online without checking the brand's specific size guide — not the generic UK sizing chart, the brand's own guide.
If you're between sizes, go up — you can always wear a belt; you can't un-suffocate yourself from a too-tight waistband.
Denim stretches. A pair of raw denim jeans that feel snug in the shop will likely ease by at least half a size after a few wears.
Check the inside leg measurement every time, not just the waist. A "32 leg" in one brand can genuinely measure 30.5 inches in another.

Never Get Your Size Wrong Again — Try Tellar

If you want to take all the guesswork out of jean shopping — and honestly, all shopping — Tellar.co.uk is the tool you need. It's the UK's leading free sizing platform, and it matches your exact measurements to over 1,500 brands instantly — no downloads, no subscription, no faffing about.

Here's how it works:

Measure once — enter your bust, waist, hips, or an existing brand size you trust.
Use the Store Size Lookup tool to get your exact size in any brand — from COS to Reiss to Everlane and beyond.
Always free — works entirely in-browser, no account needed.

For jeans specifically, it's genuinely invaluable. Because as we've established, a "size 12" means something entirely different depending on which brand you're shopping. Tellar cuts through all of that in seconds. You can also dig into The Ultimate Clothing Sizing Guide for a deeper look at how sizing works across different categories.

And if you're hunting for what denim styles are worth buying right now, the Jeans Trends 2026 edit will point you in the right direction. Tellar's Fashion Hub is packed with honest, stylist-written advice — no ads, no sponsored content, no agenda. Just good fashion information, always free.