How to Find Your Size in Straight Leg Jeans

Finding your size in straight leg jeans comes down to three measurements: waist, hips, and inseam — but knowing how to use those numbers with each brand is where most of us go wrong. I've been wearing straight leg jeans for years and I still have a pair sitting in my wardrobe with the tags on because I rushed the size check and trusted a vague "size 12" label. Lesson learned, repeatedly.

Straight leg jeans are having an absolute moment right now — they're the jeans that flatter almost every body shape, balance out wider hips, elongate shorter legs, and look equally good tucked into boots or cuffed over trainers. The only catch? Sizing is chaotic. A 28" waist in one brand is a 30" in another. Here's how to cut through the confusion and actually find your fit.

Step 1: Take Your Measurements (Properly)

I know, I know — it sounds obvious. But most of us measure once at the gym years ago and haven't revisited it since. Bodies change, and so do the measurement points brands use in their size guides.

Waist: Measure at your natural waist — the narrowest part of your torso, usually a couple of inches above your belly button. Stand up straight, breathe out naturally, and measure without sucking in.
Hips: Measure around the fullest part of your hips and bottom, usually about 8–9 inches below your natural waist. This is the number that matters most for straight leg jeans.
Inseam: Measure from your inner thigh to the floor (or have a friend help). Straight leg jeans look best hitting at the ankle or with a slight break — so your inseam length will determine whether you're cropping, cuffing, or hemming.

Write these down in both centimetres and inches — different brands use different systems and flipping between the two mid-purchase causes mistakes.

Step 2: Understand That "Your Size" Doesn't Exist Across Brands

This is the part nobody warns you about when you're starting out. A 12 in M&S fits completely differently to a 12 in Whistles, and both are a different world from a 12 in Abercrombie & Fitch. Denim especially — it varies wildly because different manufacturers use different block patterns, different stretch percentages, and different target fits.

Always go back to the brand's actual size guide and match your measurements, not your "usual size." It takes an extra 90 seconds and saves you a return.

Step 3: Know Your Rise — It Changes Everything

Straight leg jeans come in low, mid, and high rise, and getting this right is honestly as important as getting the waist measurement right.

High rise (27"+ front rise): Works beautifully for most body shapes. Elongates the leg, defines the waist, and sits comfortably above the hip. This is where I'd always start if you're unsure.
Mid rise (10–11" front rise): A good versatile option if high rise doesn't feel comfortable for you. Sits at the natural hip rather than the waist.
Low rise: Back in fashion after years in exile — but fit much more specifically. Go true to size or even down.

The Fit Test: What to Check Before You Commit

Whether you're trying on in-store or checking a returns policy online, these are the things to check:

You can slide two fingers comfortably into the waistband — no more, no less
No gaping at the back waist (a common issue if your waist is smaller than your hips — many brands now offer adjustable waistbands or stretch fabrics to help)
The leg falls straight from hip to hem without pulling at the thigh — if the fabric is pulling or creasing across the thigh, size up
You can sit down and walk without the waistband digging in
The hem hits where you want it — most straight leg styles look best ankle-length or with a half-inch break over your shoe

Best Brands for Straight Leg Jeans: My Picks by Budget

I've tried a lot of denim over the years — some brilliant, some catastrophic — so here's where I'd actually point you depending on your budget.

High Street:

ASOS — Enormous range of straight leg styles across every inseam length (including tall and petite), with detailed size guides for each style. Brilliant if you're hard to fit.
M&S — Consistently well-cut straight leg jeans with great longevity. Their magic shaping denim is particularly good for a clean, smooth silhouette.
Levi's — The 501 is the straight leg original and still one of the best. Levi's sizing runs to US measurements, so always check the size guide — but once you know your Levi's size, it's remarkably consistent.
Abercrombie & Fitch — They've quietly become one of the best denim brands on the high street. Their 90s straight and ultra high rise straight are consistently praised by style editors and customers alike for their fit across different body shapes.
Me&Em — Beautiful quality for the price point. Their straight leg styles are cut for grown women rather than teenagers, and the fabric quality is excellent.

Premium:

Whistles — Elegant, well-structured straight leg styles that work as well at work as at the weekend. Worth sizing up one if you're between sizes as the fit is on the tailored side.
Calvin Klein — Iconic for a reason. Clean lines, great denim quality, and sizing that's fairly consistent across their ranges. Their high rise straight is a wardrobe staple.

Luxury/Designer:

Citizens of Humanity — Premium denim brand beloved by stylists. Their straight leg styles have an effortless, slightly vintage quality that elevates any outfit. Sizing runs slightly small so go up if in doubt.
Paige — Exceptional denim quality and outstanding customer reviews for fit, particularly around the hips and thighs. The Noella straight is a personal favourite — it's the jeans I'd save from a house fire.

Independent brands worth knowing:

Boyish Jeans — A brilliant sustainable denim brand producing beautifully cut straight leg styles from recycled and eco-conscious fabrics. Their sizing is clear and consistent, and the quality punches well above the price.
Agolde — Cult status for good reason. Known for their 90s-inspired straight and relaxed silhouettes, Agolde is a go-to for anyone who wants elevated denim that looks genuinely considered rather than trend-led.

A Quick Note on Stretch vs Non-Stretch Denim

If you're between sizes, the fabric composition matters. Non-stretch (100% cotton) denim — like a classic Levi's 501 — will loosen slightly with wear, so going true to size or even slightly snug is fine. Stretch denim (with elastane) is more forgiving but can bag out at the knees and seat over time. If longevity matters to you, go for a higher cotton content.

Never Guess Your Size Again — Use Tellar

This is exactly why I love Tellar.co.uk — it takes all the guesswork out of sizing across every brand. Rather than spending 20 minutes cross-referencing size guides and doing mental arithmetic, Tellar matches your exact measurements to over 1,500 brands instantly. It's free, it works in your browser, and you never have to download anything.

Here's how it works:

Measure once — bust, waist, and hips, or just use a brand size you already know fits you well
Use the Store Size Lookup tool to get your precise size in any brand — from ASOS to Citizens of Humanity, Levi's to Paige
Always free — no account needed, no sponsored results, just honest sizing information

Tellar also has a brilliant Fashion Hub — a library of free, unbiased style articles written by real stylists. No ads, no brand deals, no agenda. Just honest advice. If you're working out what jeans suit your body shape, or want to know how denim sizing really works across different brands, it's a genuinely useful resource.

For more on sizing across brands, read the Ultimate Clothing Sizing Guide, or if you're deep in a denim scroll right now, the Best Jean Trends for 2025 and 2026 is worth a read too.

Ella Blake, Tellar Stylist