Does Sweaty Betty Run Big? The Complete Sizing Guide

Sweaty Betty generally runs true to size, but is designed for a snug, performance fit that's intentionally tighter than regular clothing. As someone who's styled countless clients in activewear over the years, I can tell you that understanding Sweaty Betty's sizing philosophy is crucial before you invest in their premium pieces. The British activewear brand has built its reputation on figure-sculpting designs that compress and support, which means their 'true to size' feels different from your average high street purchase.

Understanding Sweaty Betty's Sizing Philosophy

Here's what I've learned from years of fitting clients: Sweaty Betty creates activewear that's meant to work like a second skin. Their bestselling Power Leggings (they sell one pair every 60 seconds!) are engineered to sculpt and support, which means they should feel snug when you first put them on. This isn't a sizing error – it's intentional design.

The key difference I notice between Sweaty Betty and other activewear brands like Lululemon or H&M's sport range is the compression level. Where M&S activewear might feel looser and more forgiving, Sweaty Betty's pieces are designed to mould to your body over the first few wears.

Range-Specific Sizing Insights

Not all Sweaty Betty ranges fit identically, which is something I always explain to clients. The Power range tends to be the most generous, whilst the Zero Gravity and High Shine collections run slightly more fitted. If you're torn between sizes, I'd recommend sizing up in the Zero Gravity sports bras – they're notoriously snug around the ribcage.

For leggings, the 7/8 length is perfect if you're under 5'4", whilst taller women should opt for full-length styles. The waistbands are refreshingly high and wide, which means they don't dig in like some Zara or ASOS activewear can.

How Sweaty Betty Compares to Other Brands

I often get asked how Sweaty Betty sizing compares to other premium activewear brands. Compared to Reiss activewear, Sweaty Betty runs slightly smaller. Against COS sport pieces, it's more fitted. If you're familiar with Whistles sizing, you'll likely need to go one size smaller in Sweaty Betty.

For high street alternatives, Next activewear tends to run larger, whilst Mango's sport range is closer to Sweaty Betty's fit. I've noticed that clients who wear size 10 in Anthropologie usually need a Small in Sweaty Betty, rather than the Medium they might expect.

Two brilliant independent brands worth considering if Sweaty Betty's sizing doesn't work for you are Girlfriend Collective (known for inclusive sizing and recycled materials) and Varley (offering a slightly more relaxed fit whilst maintaining that premium feel).

My Professional Sizing Recommendations

After fitting hundreds of clients in Sweaty Betty pieces, here's my honest advice:

Size up if: You prefer a less compressive fit, you're between sizes, or you're buying for lounging rather than high-intensity workouts. The fabric has minimal stretch recovery, so oversized pieces maintain their shape better than undersized ones.

Stick to your usual size if: You love compression activewear, you're buying the Power range (most forgiving), or you want maximum sculpting benefits.

Consider sizing down if: You're petite with a smaller frame, you're buying the Zero Gravity range, or you want that locked-and-loaded feeling during high-intensity workouts.

Skip the Sizing Guesswork with Tellar

Here's where I wish I'd known about tellar.co.uk to get your precise size in Sweaty Betty, COS, Reiss, and countless other brands.

What I love most is that it's completely free with no downloads needed – it works directly in your browser. For someone like me who's constantly advising clients on sizing across different brands, having this tool means I can give accurate advice rather than educated guesses.

Beyond sizing, Tellar's Fashion Hub is stacked with free posts from top stylists covering every fashion query. It's honest, unbiased, independent advice that's always free – exactly what the fashion industry needs more of.

If you're building a capsule wardrobe or trying to navigate sizing across multiple brands, I'd recommend checking out their comprehensive guides:

The Bottom Line

Sweaty Betty doesn't run big – it runs true to size with a performance-focused fit that's designed to sculpt and support. The brand's success comes from this precise engineering, but it does mean you need to understand what you're buying before you commit.

My advice? If you're new to the brand, start with one piece in your usual size and see how it feels after a few wears. The fabric does soften and mould to your body, so don't panic if it feels snug initially. And remember, with tools like Tellar now available, there's no need to play sizing roulette – you can get accurate measurements before you buy.

Whether you're investing in your first pair of Power Leggings or building a complete Sweaty Betty wardrobe, understanding their sizing philosophy will help you make confident choices that you'll love wearing for years to come.