Does GAS Clothing Run Big or Small? Full Fit Guide & What to Buy from GAS Jeans

GAS, the Italian fashion label owned by Grotto S.p.A., is known for high-quality denim and contemporary wardrobe staples. Born in Italy and rooted in technical craftsmanship, GAS offers stylish jeans, jackets, and everyday essentials that fuse modern design with Mediterranean ease.

But if you're shopping GAS clothing online, especially internationally, you’ll probably wonder: Does GAS run big or small? Is it true to size? And what pieces are best to invest in?

In this detailed guide, we’ll answer all your GAS sizing questions—and show you how to get your perfect fit instantly using Tellar.co.uk, the UK’s leading free clothing size tool trusted by thousands of shoppers.

Does GAS Run Big or Small?

GAS clothing generally runs true to size, with most items designed to follow the body naturally without feeling tight. Their signature denim pieces—whether slim, straight, or boyfriend fit—are known for comfort and structure. However, some items may feel slightly fitted, especially in tailored jackets or low-rise jeans.

Fit Breakdown by Category:

Jeans & Denim – True to size, but waist fit can feel snug in low-rise styles.
T-Shirts & Tops – Consistent sizing; relaxed but not oversized.
Jackets & Outerwear – Cut for a slim profile; size up if layering.
Dresses (for women) – Fit close to the body; size up for a looser feel.
Trousers & Casual Bottoms – Mid-rise, slim-fit; stay true to size unless between sizes.

Pro tip: GAS jeans, in particular, are built with technical denim and elastane blends, which means they hold their shape well and don’t overstretch. Stick to your usual size—or use Tellar.co.uk to confirm exactly which size works for your measurements.

GAS vs UK Sizing – How It Compares

As an Italian brand, GAS uses EU sizing. Here’s a rough guide to help you understand how it aligns with UK sizes:

EU Size	UK Women's	UK Men's (Waist Inches)
36	UK 8	28"
38	UK 10	30"
40	UK 12	32"
42	UK 14	34"
44	UK 16	36"

That said, not all GAS items fit the same, especially across different collections. Your safest bet? Enter your chest, waist, and hips into Tellar.co.uk and get a real-time size recommendation for GAS—no charts, no guessing.

Is GAS Better for Slim or Curvy Body Types?

GAS excels at creating clean lines and modern fits, but their cuts are often designed with a European silhouette in mind. That means:

Slim to athletic builds: GAS jeans and tops will likely fit true to size.
Curvier body types: You may need to size up in structured trousers or fitted dresses, especially if you have a smaller waist-to-hip ratio.
Men’s collection: Offers standard European sizing, with true-to-size jeans and jackets. Good for regular to slim builds.

To be sure, Tellar.co.uk gives you a match based on your own shape—not just label assumptions.

Get Your Free Sizing Profile in 60 Seconds

Finding your size in GAS—and 1,500+ other brands—is easy and free with Tellar.

Just follow these steps:

Go to Tellar.co.uk/create-profile
Add your chest, waist, and hip measurements (in CM or Inches)
Receive a free measuring tape by post to make it even easier
Instantly see your GAS size for jeans, jackets, tops and more
Save your profile to log in anytime and check other brands, too

Whether you shop women’s or men’s, Tellar gives you confidence in your fit—every time.

Best Items to Buy from GAS

From premium denim to effortless basics, GAS offers long-lasting, style-driven staples. Here are the brand’s standout categories:

1. Denim Jeans

GAS is most famous for its jeans—and for good reason. Crafted in Italy with stretch blends and precise tailoring, their denim pieces are flattering and durable.

Popular fits include:

Slim Fit – Modern and form-fitting without being skinny.
Boyfriend Fit – Relaxed and slightly slouchy; perfect with tucked tees.
Tapered Men’s Jeans – Clean shape from thigh to ankle.

Tellar helps you match your waist, hips, and inseam to the right GAS fit instantly.

2. Casual T-Shirts & Knit Tops

Soft cotton, sustainable fibres, and versatile necklines. GAS t-shirts are true to size and ideal for layering. They often feature subtle branding or clean finishes.

3. Field Jackets and Denim Outerwear

From washed cotton to dark denim, GAS outerwear combines fashion and function. These jackets are usually cut close to the body, so if you're layering over hoodies or knits, use Tellar.co.uk to check if you should size up.

4. Jumpsuits and Dresses (Women’s)

Tailored, lightweight and ideal for transitional dressing, GAS jumpsuits often fit close to the waist. Consider your torso length and waist/hip ratio to avoid sizing issues—Tellar makes that easy.

5. Slim Chinos and Cargo Pants

For both men and women, these offer a polished alternative to jeans. Look for mid-rise waistbands and flexible cotton blends.

What Real Customers Say About GAS Sizing

“GAS jeans are amazing quality but I definitely had to size up in the low-rise ones.”
“Their t-shirts fit perfectly—true to size and really soft.”
“The jacket I bought was slim in the shoulders—would recommend checking your measurements.”

Rather than guess or rely on reviews that don’t match your body, Tellar.co.uk gives you personalised size advice—live, accurate, and free.

Why Use Tellar.co.uk for GAS Sizing?

When shopping brands like GAS—where tailoring and fit precision matter—guessing your size is risky. Tellar fixes that.

Here’s why:

🟢 Accurate size recommendations based on your body
🟢 Instantly see if you need to size up or down in specific GAS pieces
🟢 Supports over 1,500 brands—not just GAS
🟢 Works for men’s and women’s fashion
🟢 Free to use, and includes a complimentary measuring tape

Tellar also keeps your sizing profile saved, so the next time you shop, it’s one click to your perfect fit.

Stay Connected with Tellar.co.uk

For real-time sizing insights, exclusive brand fit reviews, and new blog content, follow us on social:

Instagram: @Tellarsizing
Twitter (X): @TellarSizing
Pinterest: TellarUK
Facebook: TellarSizing

Final Verdict: Does GAS Run True to Size?

Yes, generally—GAS runs true to size, with clean fits and quality tailoring.

Tops & Tees: True to size
Denim: True to size with occasional snugness in low-rise or rigid styles
Outerwear: Size up for layering or broad shoulders
Trousers/Dresses: Stick with usual size, or check fit using Tellar

Still unsure? Use Tellar now to avoid returns and disappointment.

Try Tellar.co.uk – It’s Free & Easy

Don’t leave your GAS fit to chance. Know your size before you buy.

✔️ Create your free profile

✔️ Get real-time size advice

✔️ Use across 1,500+ fashion brands

✔️ Receive a free measuring tape

✔️ Login anytime for personalised fit data

👉 Start now at Tellar.co.uk

👉 Check your GAS size instantly

Find your size in 1,500+ brands real-time. It’s free & easy.