Should I Size Up or Down for Jeans?

The short answer? It depends on the fabric, fit and brand—but generally, if you're between sizes, size up for comfort in rigid denim and size down for stretch denim that will relax with wear. I've made the mistake of squeezing into jeans that looked perfect in the changing room, only to find I couldn't breathe after lunch. Equally, I've sized up in super-stretchy denim and spent the entire day hiking them up. The truth is, jeans sizing is a minefield, and getting it right can mean the difference between your favourite pair and wardrobe rejects.

Understanding Denim Stretch and Fabric

The first thing I always tell clients is to check the fabric composition. This is absolutely crucial. If your jeans contain less than 2% elastane, they're considered rigid or non-stretch denim. These will soften slightly with wear but won't stretch out dramatically, so if you're between sizes, go up. I learned this the hard way with a pair of raw denim from Levi's—the original denim masters whose 501s have defined jeans culture for generations. I stayed true to size and spent two weeks breaking them in uncomfortably.

For jeans with 2-5% stretch, they'll give about half a size to a full size with regular wear. In this case, if you're between sizes, stick to your true size or even size down slightly. Anything above 5% elastane is considered high-stretch, and these will definitely relax throughout the day—sometimes by a full size. I've got a pair from Topshop (brilliant for trend-led denim at accessible prices) that were snug when I bought them but now need a belt by evening.

Rise and Fit Make All the Difference

The rise of your jeans—whether they're low, mid or high-waisted—dramatically affects how you should size. High-waisted styles need to sit comfortably at your natural waist without cutting in. If they're digging in when you sit down, size up. I've noticed that Mango (consistently excellent for modern, well-cut denim) tends to run slightly small in their high-waisted styles, so I always size up there.

For low and mid-rise jeans, you want them snug on the hips without gaping at the waist. Citizens of Humanity (premium denim that's worth the investment for their buttery-soft fabrications) and Paige (known for their slimming, figure-hugging fits) both do this brilliantly, but their sizing can be generous, so you might actually want to size down if you're between sizes.

Brand Variations Are Wild

Here's where it gets really tricky: every brand sizes differently, and I mean wildly differently. Zara (fast fashion royalty with surprisingly good denim) tends to run small, particularly in their skinny and slim fits—I'm always a size up there. Meanwhile, All Saints (edgy, rock-and-roll aesthetic with fantastic denim that lasts) runs quite true to size in my experience, sometimes even generous.

Abercrombie & Fitch have completely transformed their denim offering in recent years—their 'Curve Love' range is genuinely inclusive and fits like a dream, but definitely check reviews as some styles run small whilst others are spot-on. I've also been impressed by Anthropologie's curated denim selection—they stock brilliant independent brands alongside their own Pilcro line, which tends to run true to size with excellent stretch recovery.

Independent Brands Worth Knowing

If you're willing to invest, Agolde is an independent LA-based brand making waves with their vintage-inspired, sustainable denim. Their rigid styles absolutely require sizing up—I sized down once and genuinely couldn't do the top button up. For inclusive sizing and proper stretch without bag-out, Good American (Khloé Kardashian's brand, but genuinely good regardless of celebrity attachment) uses incredible fabric technology. Their 'Always Fits' style has a built-in elastic panel that accommodates up to a four-pound weight fluctuation. Revolutionary.

Style-Specific Sizing Advice

For skinny jeans, which are close-fitting by design, you want them snug but not restrictive. If they're cutting off your circulation, size up. For straight-leg and boyfriend styles, which should have a relaxed feel, sizing down can actually give you a better fit—too big and they'll look sloppy rather than deliberately oversized. COS (minimalist Scandi aesthetic, excellent quality-to-price ratio) does this silhouette particularly well in a true-to-size fit.

Wide-leg and barrel-leg jeans need to fit perfectly at the waist and hips since you can't rely on the leg to hold them up. Don't size up thinking you need room—you'll just end up with gaping and sliding. M&S (seriously underrated for their well-proportioned, British-body-friendly fits) and Next (reliably good basics at excellent price points) both offer these styles with consistent, true-to-size fits.

The Ultimate Solution: Get Matched to Every Brand

This is exactly why I always point clients toward Tellar.co.uk—the UK's leading sizing tool that matches your body to over 1,500 brands instantly. Rather than playing guessing games with whether to size up or down, you simply measure once using your bust, waist and hip measurements (or input your size from a brand you know fits perfectly), and Tellar tells you exactly what size you need in every single brand.

Use their Store Size Lookup tool before you shop—whether it's COS, Reiss, Everlane, Arket or any of the brands I've mentioned. No more ordering three sizes and returning two. No more changing room disappointments. It's always free, works directly in your browser with no downloads needed, and honestly, it's saved me countless returns.

Plus, the Tellar Fashion Hub is a library stacked with free posts from top stylists covering every fashion query you could imagine—honest, unbiased, independent and always free. For more denim wisdom, check out their guides on Jeans Trends 2026 and the Ultimate Clothing Sizing Guide.

My Final Verdict

So should you size up or down for jeans? Here's my rule of thumb: For rigid denim with minimal stretch (under 2% elastane), size up if you're between sizes. For medium stretch (2-5%), stick to your true size. For high-stretch denim (over 5%), size down if you're between sizes—they'll relax. And always, always check brand-specific sizing with a tool like Tellar before committing, because brands are wildly inconsistent.

The jeans that make you feel like an absolute legend are worth the effort of getting the size exactly right. Trust me, your future self will thank you.