What Is Sizing Like at Mountain Warehouse?

By Ella Blake — Fashion Stylist | Tellar Fashion Hub — Always honest, unbiased & unsponsored

Mountain Warehouse sizing runs true to standard UK sizes — but with one important caveat: their outerwear and mid-layers are cut with a slightly generous fit to allow for layering underneath, so if you're between sizes or tend to wear slim-fitting clothes, sizing down in jackets and fleeces will give you a much more flattering result.

I'll be straight with you — I wasn't always a Mountain Warehouse convert. A few years ago I'd have walked past it without a second glance. Then I got dragged on a last-minute trip to the Lake District with absolutely zero appropriate kit, ended up panic-buying a waterproof in a service station Mountain Warehouse and — somewhat embarrassingly — it was brilliant. I ordered the same size I wear in most brands (a 12), it fitted perfectly over a chunky knit, and it kept me completely dry through what I can only describe as a biblical downpour. Sometimes the outdoors brands really do deliver.

How Mountain Warehouse Sizing Works Generally

Mountain Warehouse follows standard UK women's sizing across its full range, which runs from a UK 8 through to a UK 20 in most lines. They also offer a Plus range that extends further. Here's what I've noticed across different product categories:

Outerwear and waterproof jackets: Cut with a roomier fit to allow base and mid-layers underneath — if you want it to look smart rather than boxy, go down a size.
Fleeces: True to size, with a relaxed (but not oversized) cut. A size 12 fits like a size 12.
Base layers: True to size for regular fit. Size down if you want a close, thermal fit (which is actually more effective for heat retention anyway).
Walking trousers and leggings: True to size. Mountain Warehouse offers multiple leg length options on trousers, which is genuinely helpful for petite and tall shoppers — not every brand bothers.
Ski and snow gear: Runs slightly large — definitely size down here if you want a sleek fit rather than the marshmallow look.
Casual and lifestyle range: Pretty much spot-on UK sizing throughout.

Mountain Warehouse Women's Size Conversion Table

Garment-by-Garment Breakdown

Because outdoor clothing is so category-specific, here's a quick run-through of the most popular Mountain Warehouse buys and exactly how they fit:

Waterproof jackets (e.g. Pakka, Exodus range): I'd recommend sizing down one — the extra volume in the standard size is designed to accommodate a mid-layer and it can look oversized if you're wearing just a t-shirt underneath.
Snowdonia and similar insulated jackets: Again, go down if it's purely for casual wear. Stick to your true size if you're genuinely layering for cold weather.
Fleeces: True to size. Lovely relaxed fit on the Fell range in particular — surprisingly stylish for a budget fleece.
Walking trousers: True to size. Always check the inseam — the short/regular/long leg options are a genuine feature worth using rather than ignoring.
Leggings and base layers: True to size. Size down for thermal compression benefit.
Footwear: True to size — I'd suggest ordering your usual UK shoe size and you should be absolutely fine.

My Honest Verdict on Mountain Warehouse Quality

Look — it's not Arc'teryx. You're not paying Arc'teryx prices either, and I think that's the point people sometimes miss. For everyday outdoors use, dog walking, weekend hiking, and festivals, Mountain Warehouse is genuinely excellent value. The waterproofing on their better jacket lines performs well and holds up to proper British weather, which (as we all know) is no small ask.

Where I'd be more cautious is with very serious technical mountaineering or extreme cold-weather gear — for those you'd want a more specialist brand. But for the vast majority of us who want functional, decent-looking outdoor clothing without spending a fortune? Mountain Warehouse absolutely delivers.

If You Like Mountain Warehouse, You Might Also Love…

Whether you want something at a similar price point, something a bit more premium, or just want to explore alternatives with a slightly different aesthetic, here are my picks — chosen specifically for their outdoor and active credentials rather than just the usual suspects:

High Street & Accessible Brands

Fat Face — Brilliant for the outdoorsy-but-stylish gap. Their fleeces and lightweight jackets have a much more fashion-forward cut than most outdoor brands, and the sizing is consistent and reliable.
Seasalt Cornwall — If you want practical and genuinely beautiful at the same time. Their waterproof-treated outerwear and layering pieces are made for proper British weather and the fits are consistently true to size.
Joules — A go-to for country and outdoor dressing with a bit more personality. Particularly strong on rain jackets and welly-friendly boots. Sizing runs true throughout.
Barbour — Iconic for good reason. The wax jackets are an investment but they last forever, and the quilted liner jackets are a brilliant versatile alternative to a standard padded coat. True to size in women's.
Timberland — Outstanding for outdoor footwear and durable casual clothing. Their women's styles have improved hugely in recent years and the sizing is spot on.
Superdry — Great for ski and snow-sport style at an accessible price. Their technical jackets are strong performers and the sizing is generally true to UK standard.
Sweaty Betty — If you want activewear that crosses over into outdoor use, Sweaty Betty's leggings and running/hiking layers are exceptional quality and the fit is very consistent across sizes.

Premium Picks

Gant — For that Scandi outdoor-casual crossover. Their technical knitwear and lightweight jackets are particularly good for autumn and transitional dressing. Sizing runs true.
Tommy Hilfiger — Underrated for outdoor-adjacent casual wear. Their puffers and quilted jackets are well-made and reliably sized.

Two Independent Brands Worth Knowing

Finisterre — A brilliant Cornish brand built around cold-water surfing and outdoor adventure. Sustainably made, genuinely functional, and beautifully designed. Their sizing is true to UK standard and the quality is noticeably above the high street. Highly recommended if you want something a bit more considered than the big outdoor chains.
Passenger Clothing — A small independent brand for outdoor and adventure dressing with a really strong ethical ethos. Great fleeces, lightweight jackets, and casual outdoor pieces. Their sizing is consistent and slightly more fashion-forward in its cut. A really lovely find if you haven't come across them yet.

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