How to Find Your Size in Leggings — Because "Just Stretchy" Is Not a Sizing Strategy

By Ella Blake, Tellar Stylist

Finding your size in leggings comes down to your hip measurement and your inside leg length — and before you say "but leggings just stretch," hear me out, because that attitude is exactly why so many of us end up with pairs that go see-through when we bend down, or bunch unattractively at the ankle, or sag in the crotch within twenty minutes of wearing. I've made every single one of these mistakes. The see-through squat test failure at a yoga class in 2019 was a particular low point. Leggings sizing matters — genuinely.

Why Leggings Sizing Is More Nuanced Than You Think

The "one size fits all" stretch myth is one of fashion's most persistent lies. Yes, leggings have elasticity — but that elasticity has limits, and when you push past them, the fabric thins out, loses its opacity, and the whole thing stops looking like a deliberate outfit choice. Good leggings should fit snugly without pulling. The fabric should sit smoothly across the hip and thigh without any puckering, and the waistband should stay put without digging in or rolling down. Getting there requires knowing your numbers.

The Two Measurements You Actually Need

Grab a soft tape measure and note down:

• Hips: Measure around the fullest part of your hips — usually about 8 inches below your natural waist. This is your most important number for leggings, as it determines whether the fabric will stretch too thin across the seat and thigh.

• Inside leg / inseam: Measure from your crotch to your ankle bone. This dictates whether full-length leggings will actually reach your ankle or end up as accidental cropped leggings (which is frustrating if that wasn't the plan).

• Waist (optional but useful): Especially relevant for high-waisted styles, where the waistband needs to sit comfortably without rolling down or cutting in.

What the Size Labels Actually Mean — Brand by Brand

This is where it gets interesting, because leggings brands size very differently from one another. Here's what I've found:

• Lululemon sizes their leggings quite small — if you're between sizes, size up. Their Align leggings in particular run narrow through the hip. The quality is exceptional but the sizing is notoriously inconsistent between styles, so always check the specific product's size guide rather than assuming your Lululemon size carries across.

• Sweaty Betty tends to run true to size and is consistently reliable. Their Power leggings are one of the few pairs I'd trust to be genuinely opaque under pressure — they're cut generously through the seat, which is a huge plus.

• Gymshark runs small, particularly through the waist. Go up a size if you're on the border. Their Vital Seamless leggings are a particular favourite and worth the slight sizing faff to get right.

• Asos own-brand leggings are a mixed bag — sizing can vary significantly between styles. Read the reviews religiously before buying, because other shoppers will always flag if a pair runs small or large.

• M&S leggings are brilliantly consistent and come in short, regular, and long lengths, which is genuinely useful. Their Goodmove activewear line is excellent quality and sizes accurately.

• H&M leggings tend to size generously — if you're between sizes, go down rather than up. Their jersey leggings for everyday wear are great value but can thin out with repeat washing, so factor that in.

• Boden do a fantastic everyday legging that sizes true and comes in multiple lengths. Less sporty, more lifestyle — brilliant under tunics and long knits.

• Urban Outfitters sizing varies wildly by style — always check the individual product guide and lean on the reviews for fit feedback.

The Opacity Test — Non-Negotiable Before You Commit

Before you wear any new pair of leggings out of the house, do this: put them on, stand in front of a mirror in good light, and bend forward. If you can see through the fabric, size up or ditch the pair entirely. No amount of styling will save you from that particular humiliation in public — I cannot stress this enough. The bend test is your best friend. I now do it religiously with every new pair before I leave the house, let alone the fitting room.

Full Length vs. 7/8 vs. Cropped — What Works for Your Height

Leggings come in several lengths and it matters enormously for how they look:

• Full length (typically 28–30" inseam): Best for women 5'6" and above. Should reach the ankle bone cleanly.

• 7/8 length (typically 25–27" inseam): Flattering on most heights — sits just above the ankle and is particularly good for petite frames as it avoids the bunching that can happen with full-length pairs.

• Cropped (typically 20–23" inseam): Best worn intentionally — brilliant for showing off trainers or worn with a long top if you're shorter.

If you're petite (under 5'4"), I'd always reach for a 7/8 length as your default. Next and M&S are your friends here, with their multiple-length options saving you from the alteration process entirely.

High Waist vs. Mid Rise — Which Fits Better?

High-waisted leggings are, in my opinion, almost universally more flattering — they hold everything in, stay put during movement, and create a much cleaner line under cropped tops and longer layers. But they do require a longer rise measurement to sit correctly. If you find high-waisted leggings consistently roll down or feel uncomfortable, the issue is usually that the rise is too short for your proportions — try a different brand rather than assuming high-waist isn't for you. Lululemon, Sweaty Betty, and Gymshark all have excellent high-rise cuts that are worth trying side by side to find which rise length suits your torso.

Everyday Leggings vs. Activewear — Different Sizing Rules Apply

It's worth noting that fashion leggings (think jersey, ponte, or faux-leather styles) and activewear leggings size differently, because they're made from different fabrics with different stretch ratios. A compression-fabric gym legging is designed to feel snug — that's intentional and correct. A jersey fashion legging that feels that tight is simply the wrong size. Don't conflate the two. Hush does a brilliant everyday jersey legging that's more relaxed in fit, while All Saints does an excellent faux-leather legging that sizes true but requires you to be realistic about your measurements — there's no stretch to hide behind with faux leather.

Two Independent Brands Worth Knowing

Girlfriend Collective is a US-based brand widely available in the UK that makes genuinely excellent leggings from recycled materials — sizing is inclusive (XS–6XL), runs true to size, and the fabric is consistently opaque. They publish incredibly detailed size guides which makes online buying genuinely easy. And Organic Basics is a brilliant Scandinavian brand whose everyday leggings are made from TENCEL and recycled nylon — they size true, feel incredible against the skin, and are worth every penny for a pair you'll wear constantly.

My Biggest Leggings Mistake — Learn From It

For years I bought leggings based on my dress size rather than my hip measurement, which meant I was consistently buying pairs that were slightly too small across the seat. The result? Fabric that looked fine in the changing room but went pale and strained across the backside the moment I sat down. The fix took about thirty seconds — measuring my hips properly and matching to the brand's size guide — and I haven't had the problem since. It sounds obvious in retrospect, but so many of us skip this step.

Find Your Exact Leggings Size Across 1,500+ Brands — Free, Instantly

If you want to stop second-guessing your size across different brands, Tellar.co.uk is the UK's leading free sizing tool. Enter your measurements once and get your precise size in over 1,500 brands instantly — no downloads, no subscriptions, no faff.

• Measure once — hip, waist, or inside leg — and let Tellar do the rest

• Use the Store Size Lookup tool to find your exact size in any brand, from Lululemon to M&S to Gymshark and beyond

• Always free — works in-browser, no account needed

Want to understand how brand sizing actually works? Our Ultimate Clothing Sizing Guide breaks it all down — from vanity sizing to international size conversions — in plain English.

And if you're thinking about your wardrobe more broadly, don't miss the Tellar Fashion Hub — a free library of honest, unsponsored style advice. Our Ultimate Guide to Jackets is a great place to start building a wardrobe that actually works for your shape and size.