Does the Brand Mountain Warehouse Run Big or Small? What Is Their Sizing Like & What’s Worth Buying?
Author: Stylist and brand team at Tellar
Date: 2025
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Mountain Warehouse is a go-to brand for affordable outdoor clothing, ski gear, walking boots and waterproof jackets. Whether you’re hiking in Snowdonia, skiing in Val Thorens, or just walking the dog on a rainy UK day, the brand is known for practical, weather-ready apparel. But when it comes to shopping online, many customers still ask: Does Mountain Warehouse run big or small?
📌 If you only read one part of this post, here’s the key: Tellar.co.uk matches your exact measurements to Mountain Warehouse—and over 1,500 brands—with a quick, free setup. You’ll get a free measuring tape, and we’ve already analysed every fit detail, so you never need to check a size chart again. No guesswork, no catches—just your perfect outdoor fit.
Who Shops at Mountain Warehouse?
Founded in the UK in 1997, Mountain Warehouse offers outdoor clothing and gear for:
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Men, women and kids
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Hikers, skiers, and campers
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Commuters, dog walkers, and festival goers
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Budget-conscious shoppers looking for good technical gear
They’re known for accessible pricing, wide size ranges, and consistent restocks. But sizing can still be confusing—especially across waterproofs, fleeces, base layers, and shoes.
So, Does Mountain Warehouse Run Big or Small?
In general: Mountain Warehouse runs true to size—but some jackets, base layers and walking trousers can run slightly small, especially if worn over other layers.
For Women:
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Waterproof jackets: True to size in general, but can run tight in the hips and bust
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Fleeces and base layers: Cut close to the body—size up if you want layering room
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Trousers and leggings: Waistbands may feel snug—go up a size if between
For Men:
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Puffer and down jackets: True to size, with decent shoulder and chest room
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Base layers and tops: Slim fit—size up if muscular or broad
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Cargo trousers and hiking trousers: Generally true to waist, snug in the thigh
Want a fit based on your actual measurements? Use Tellar’s tool and we’ll match you to Mountain Warehouse’s best-fitting size in seconds.
Mountain Warehouse vs UK High Street Sizing
Mountain Warehouse sticks to UK sizing standards (8–20 for women, S–XXL for men), but they cut for layering—so sizing may not match high-street fashion brands.
Size Label |
UK Size |
Tellar Fit Tip |
|---|---|---|
Women’s 10 (S) |
UK 10 |
True to size if worn alone |
Women’s 12 (M) |
UK 12 |
Size up for hip or bust layering room |
Men’s M |
UK 38–40 chest |
True to size, snug over fleeces |
Men’s L |
UK 42–44 chest |
Size up for winter layering |
➡️ Tellar.co.uk handles all of this for you—converting, adjusting and recommending the exact size based on your chest, waist, hips and height.
Fabric Fit Guide: Why Layering Affects Fit in Outdoor Brands
Mountain Warehouse uses technical outdoor fabrics—many of which affect how the clothing feels on the body.
🧥 Waterproof Jackets (IsoDry, IsoTex)
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Designed to be windproof and rain-resistant
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Often lined, slightly stiff
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Fit tip: True to size—but size up for thick fleece or jumper underneath
🧶 Fleece & Microfleece
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Stretchy and light, cut close to the body
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Fit tip: Size up for a relaxed fit, true to size for heat retention
🏃 Base Layers (Merino / Polyester)
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Moisture-wicking, snug fit
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Fit tip: Meant to fit tight—but size up if you don’t want compression
👖 Hiking Trousers
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Ripstop or stretch fabric with zip pockets
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Some are lined for winter
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Fit tip: Size up in the waist if curvier or muscular through thigh
Bestselling Mountain Warehouse Items & How They Fit
1. Seasons Waterproof Jacket
Best for rain protection, school runs, and walking holidays.
➡️ Fit tip: True to size in shoulders—size up if layering over chunky knitwear
2. Talus Women’s Walking Trousers
Stretch fit, multiple pockets, ideal for active wear.
➡️ Fit tip: Snug through bum and thigh—go up a size for all-day comfort
3. Merino Base Layers
Popular for skiing, cold-weather hiking, and camping.
➡️ Fit tip: True to size but tight-fitting—size up if you don’t want compression
4. IsoCool Performance T-Shirts
Great for summer hikes and activewear.
➡️ Fit tip: Slightly fitted—true to size or size up for looser feel
5. Lightweight Puffer Jackets
Packable, warm and great for layering.
➡️ Fit tip: True to size—generous enough for light layers underneath
Mountain Warehouse vs Other Outdoor Brands
Brand |
Fit Compared to Mountain Warehouse |
|---|---|
Regatta |
Similar sizing, slightly roomier |
Columbia |
Mountain Warehouse is truer to size |
The North Face |
North Face runs smaller in jackets |
Craghoppers |
Craghoppers is more generous |
Berghaus |
More technical and fitted overall |
🧭 Compare them all with Tellar and find your best fit in seconds.
Common Fit Complaints (And How Tellar Fixes Them)
❌ “The coat fit in the chest but felt tight in the hips.”
Tellar adjusts for body shape variations, including bust-to-hip ratio.
❌ “The trousers were too tight in the thighs but loose in the waist.”
Tellar maps your hip and thigh proportions to trousers in real product data.
❌ “I didn’t know whether to size up for base layers.”
Tellar understands how you want to wear it—tight for warmth or loose for comfort—and gives guidance accordingly.
Why Use Tellar Before Shopping Mountain Warehouse?
Tellar.co.uk is the UK’s most advanced size-matching tool—free to use, easy to set up, and built to save you from returns and frustration.
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✅ Enter your chest, waist, hips and height just once
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✅ Get your exact size in Mountain Warehouse + 1,500 other brands
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✅ Free tape measure posted to your door
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✅ Compare sizing across similar outdoor brands
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✅ No more size chart confusion—we’ve done the data work
🎯 Create your free Tellar profile now and shop smarter across outdoor and fashion brands.
Related Tellar Sizing Guides
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Final Thoughts: Mountain Warehouse Sizing is Reliable—But Not Always Layer-Friendly
Mountain Warehouse offers good value and strong sizing consistency, but many pieces are designed with technical layering in mind, so you need to choose your size accordingly. If you wear fleece or thermals underneath, or are curvy through hips or chest, a standard UK 10 may feel like a small 8.
Tellar.co.uk fixes all of this. We’ll match you to the exact Mountain Warehouse size—based on you, not guesswork. Whether you're shopping for waterproofs, walking gear, or winter thermals, get it right the first time.
“Find your size in 1,500+ brands real-time. It’s free & easy.”