Lululemon Sizing Guide: Should You Size Up? 25" vs 28" Inseam Explained

Lululemon generally runs true to size, but specific styles require sizing adjustments—particularly compressive fabrics like Everlux and tops with built-in bras, which tend to run small. I learnt this the expensive way when I ordered my first Swiftly top in my usual size and could barely breathe in it, let alone do a downward dog without feeling like a sausage in casing. Not my finest fashion moment.

Understanding Lululemon's Sizing System

Lululemon uses US numerical sizing (0, 2, 4, 6, 8, etc.) for most items, with some casual pieces using standard alpha sizing (XS, S, M, L). Think of their size 4 as an XS in typical UK sizing, a size 6 as a small, and so on. It's confusing at first, but once you crack the code, it becomes second nature.

The brand's size charts are remarkably accurate—genuinely one of the best I've encountered. Measure your bust, waist, and hips properly (in your underwear, no cheating by holding your breath!), and their chart will steer you right for most styles. That said, the devil's in the details, and certain fabrics and cuts require strategic sizing.

When to Stick With Your True Size

Wunder Train LeggingsThese are Lululemon's workhorse leggings, and they run absolutely true to size. The Everlux fabric has enough compression to feel supportive without being restrictive. I wear my usual size 6, and they're perfect—snug enough to stay put during burpees, but not so tight that I'm counting down the minutes until I can peel them off.

Fast & Free LeggingsAnother true-to-size winner. The Nulux fabric is slick and sweat-wicking, ideal for high-intensity workouts. These don't stretch out during wear, so your true size will maintain its shape beautifully throughout even the sweatiest HIIT class.

Basic Tops Without Built-in BrasSimple tanks, tees, and long-sleeves run true to size. No surprises here—order your usual size and you're sorted.

When You Absolutely Should Size Up

Swiftly Tops (Long and Short Sleeve)This is crucial: Swiftly tops run small. Not just a bit small—properly, noticeably small. The seamless construction and technical fabric mean there's less give than you'd expect. Your true size might technically fit, but it'll create unflattering bulging around your waist and hips. Size up one full size, trust me. I now own three Swiftly tops in size 8 instead of my usual 6, and the difference is night and day.

In Movement TightsThe Everlux fabric in these is seriously compressive—more so than the Wunder Trains. If you like a supportive feel, your true size works, but if you prefer comfort over compression, definitely size up. I tried both, and the size up felt infinitely better for longer yoga sessions.

Built-in Bra Tops and TanksAnything with integrated bra support runs tight, particularly across the bust. If you're between sizes or have a larger chest, absolutely size up. The compression can be overwhelming otherwise, and there's nothing worse than adjusting your top every thirty seconds during a workout.

Dresses and Evening WearLululemon dresses run surprisingly small, especially if you're a size 4 or under. They're cut quite fitted through the body, so sizing up ensures you're comfortable and can actually move. I made the mistake of ordering my usual size in the Court Rival dress and could barely sit down. Not ideal.

When You Can Size Down

Align LeggingsThe legendary Aligns have an enormous amount of stretch—they're made from Nulu fabric, which is buttery soft and incredibly forgiving. Many people size down in these because they don't offer much compression and can stretch out slightly with wear. That said, your true size absolutely works if you prefer a more relaxed fit. I stick with my true size because I wear them for gentle yoga and lounging, not intense workouts.

Word of warning: Aligns are prone to pilling if you're not careful. Never put them in the tumble dryer, avoid wearing them for high-friction activities like running, and wash them inside out. They're not built for intensity—they're built for comfort.

The Great Inseam Debate: 25" vs 28"

This is where Lululemon gets really clever. Offering multiple inseam lengths means you can actually get leggings that fit properly, which is revolutionary if you've spent years dealing with excess fabric bunching at your ankles or leggings that awkwardly stop mid-calf.

The 25" Inseam

The 25" inseam is designed as a 7/8 length—intentionally cropped to hit just above the ankle. On someone around 5'5" to 5'8", it creates that modern, sporty look that shows a bit of ankle and pairs brilliantly with trainers.

Perfect for:

• Anyone 5'4" and under who wants a true full-length fit with zero bunching

• People 5'5"-5'8" who love the trendy cropped aesthetic

• Those who hate fabric pooling at the ankles

• Warmer climates or heated studio workouts where you want maximum breathability

• Showing off your favourite trainers or shoes

I'm 5'3", and the 23" inseam is actually my sweet spot for full-length, but when I want that slightly cropped look, the 25" is gorgeous. It hits right at my ankle bone—very flattering, very deliberate.

The 28" Inseam

The 28" is Lululemon's standard full-length offering. It's designed to hit at or just below the ankle bone for people of average height, providing complete coverage from waist to shoe.

Perfect for:

• Anyone 5'6" and taller who wants proper full-length coverage

• People who prefer the traditional athletic legging look

• Colder climates where ankle coverage provides extra warmth

• Those who don't mind a bit of scrunching at the bottom (or plan to use Lululemon's free hemming service)

• Very tall individuals (5'9"+) who find the 25" ends awkwardly mid-calf

If you're under 5'4", the 28" will almost certainly bunch at your ankles unless you get them hemmed. Lululemon offers free hemming in stores, which is brilliant, but honestly, it's easier to just order the right length from the start.

Other Inseam Options Worth Knowing

Lululemon also offers 21", 23", and 31" inseams depending on the style. The 21" is a proper cropped capri length. The 23" is perfect for petite full-length (I live in these). The 31" is for tall individuals who need that extra coverage. Don't be afraid to try different lengths—the right inseam makes all the difference to how polished and intentional your outfit looks.

Fabric Matters More Than You Think

Nulu (Align Leggings)Buttery soft, minimal compression, prone to pilling. Best for yoga, lounging, low-impact activities. Not sweat-wicking enough for intense cardio.

Everlux (Wunder Train, In Movement)Supportive compression, excellent sweat-wicking, cool to the touch. Perfect for hot yoga, HIIT, running. The In Movement version is more compressive than Wunder Train.

Nulux (Fast & Free)Slick, lightweight, incredibly sweat-wicking. Designed for running and high-intensity training. Less soft than Nulu but far more durable.

Luon (Older Styles)Lululemon's original fabric—thicker, more compressive, holds its shape well. You'll find this in older Wunder Under styles. It's less common now but still brilliant for those who want serious compression.

Real Talk: What Actually Works

After years of trial and error (and quite a few returns), here's my personal Lululemon wardrobe strategy:

• Align Leggings (23" inseam, size 6) - My go-to for gentle yoga, Pilates, and weekend errands

• Wunder Train (23" inseam, size 6) - For proper workouts where I need things to stay put

• Swiftly Long Sleeve (size 8, not 6!) - Perfect for running in cooler weather

• Define Jacket (size 6) - The most flattering jacket I own, brilliant for throwing over gym kit

The common thread? I sized up in the Swiftly because it runs small, stuck with my true size for leggings, and chose inseams based on my height. No rocket science—just knowing which styles run true and which don't.

High Street Alternatives If Lululemon's Not Your Budget

Look, Lululemon is expensive. A pair of leggings is £98+, which is a lot to spend if you're not entirely sure about sizing. Here are some alternatives that offer similar quality:

Sweaty Betty - UK-based, excellent quality, often better for curvier figures. Their Power leggings are legendary and actually stay put during workouts. Sizing runs fairly true, and they offer petite and tall options.

Girlfriend Collective - Sustainable activewear made from recycled materials. Their compressive leggings are brilliant, and they're far more size-inclusive than Lululemon (XS-6XL). Slightly less expensive too.

Gymshark - Much cheaper, decent quality for the price point. The Flex and Vital ranges are popular, though sizing can be inconsistent. Order two sizes if you're unsure.

Lululemon alternatives at ASOS - ASOS carries loads of activewear brands at various price points. ASOS 4505 is their own-brand technical range and surprisingly good. Monki does affordable basics that work for low-impact activities.

Where to Buy Lululemon in the UK

You can shop Lululemon directly from their UK website or visit their stores in major cities (London has several, plus locations in Edinburgh, Manchester, Birmingham, etc.). The in-store experience is genuinely helpful—their "educators" actually know the products and can guide you on sizing.

They also have an excellent outlet section online called "We Made Too Much" where you can find past-season colours at reduced prices. Same quality, same sizing, just last season's colours. I've nabbed some brilliant pieces there.

The Sizing Solution You've Been Ignoring

Here's the frustrating bit about Lululemon sizing—or any activewear sizing, really. You spend ages researching whether to size up or down, reading reviews, comparing inseams, and then you still order the wrong size because every brand is different. A size 6 in Lululemon is not the same as a size 6 in Sweaty Betty or Gymshark or Nike.

This is precisely why Tellar.co.uk exists. You measure yourself once—bust, waist, hips—and it tells you your exact size in over 1,500 brands instantly. No more guessing, no more size chart confusion, no more ordering three sizes "just in case."

Use the Store Size Lookup tool to find your precise Lululemon size (and your Sweaty Betty size, and your Reiss size, and your Zara size) all at once. It works in your browser, it's completely free, and it's genuinely life-changing if you're sick of the returns carousel.

Plus, the Tellar Fashion Hub has loads of honest styling advice and brand recommendations. No sponsors, no bias, just proper expertise. Check out the ultimate clothing sizing guide for more details on how different brands size their garments, or browse their jacket guide if you're expanding beyond activewear.

Final Sizing Tips

• Measure yourself properly - Use a flexible tape measure, wear minimal clothing, and don't pull the tape too tight

• Read product reviews - Lululemon's website has brilliant reviews where people specify their measurements and which size they ordered

• Know your height - Inseam choice is more important than you think for achieving a polished look

• Consider the activity - High-intensity workouts need more compression; gentle yoga can be more relaxed

• Don't put Nulu in the dryer - Seriously, it'll pill like mad. Air dry everything

• Take advantage of free hemming - If you're between lengths, buy longer and get them hemmed in store

The Bottom Line

Lululemon sizing is generally reliable—stick with your true size for most leggings, size up for Swiftly tops and built-in bra items, and choose your inseam based on your height and preference. The 25" works brilliantly for anyone under 5'4" or those wanting a cropped look, whilst the 28" is ideal for taller individuals or anyone preferring full coverage.

Yes, it's expensive. Yes, the sizing can be confusing at first. But once you find your perfect fit, Lululemon pieces genuinely last for years. I've got Align leggings from 2019 that are still going strong (because I never put them in the dryer, obviously).

And honestly? Use a sizing tool like Tellar to remove the guesswork entirely. Life's too short for sizing anxiety and multiple returns. Get the right size first time, and actually enjoy your new kit instead of stressing about whether it'll fit.