What Is Sizing Like at Castore Menswear?

Castore runs slim and athletic. If you're lean and want a fitted look, take your usual size. If you're between sizes, carry any weight through the chest or middle, or just prefer breathing room, size up. That's the honest one-line answer, and it's the one I give clients before they've even finished asking. Castore is cut for a performance body, not a relaxed one — so the fit surprises a lot of blokes who are used to high-street sizing.

I've dressed enough men in Castore over the last few years to know where it catches people out, so let me break it down properly.

How Castore actually fits

Castore is a British premium sportswear brand, and everything they make is engineered around a slim, athletic silhouette. Even the pieces they label "regular fit" sit closer to the body than you'd expect. The tightest points are almost always the same three: shoulders, chest and biceps. If you lift, cycle or play any kind of racquet sport, that's exactly where you'll feel it.

The trickier issue is that sizing isn't perfectly consistent across their ranges. Here's how it tends to break down:

Replica and team kits — these run the tightest. A home or away shirt in your normal size will often feel snug across the chest. This is the range where I most often tell people to go up.
Training and casual gear (tees, quarter-zips, hoodies, joggers) — closer to true-to-size, but still a fitted cut. If you like a bit of room, or you're layering, size up here too.
Outerwear and tech jackets — watch the arm length as much as the body. I've seen the sleeves come up shorter than expected, so if you've got a long reach, factor that in.

A quick confession from my own wardrobe

I'll be straight with you — Castore has caught me out personally. I bought a training quarter-zip in my usual large, convinced I knew my size, and couldn't get it comfortably over the shoulders without it pulling. Straight back to the shop for an XL, which draped perfectly. Lesson learned. On the flip side, when I bought a replica top and deliberately went up a size, it hung exactly how I wanted — clean lines, no cling. Sizing up on Castore has genuinely never let me down.

Coming from Nike or Adidas?

Worth knowing: if your reference point is Nike or Adidas "standard" fit, Castore will feel noticeably more fitted, particularly across the upper body. It's not a fault — it's the design brief. It's built to look sharp on and off the pitch. Just don't assume a medium in one is a medium in the other.

How I'd style it

Castore lives in that smart-athletic lane, so lean into it rather than fighting it:

A fitted training top under an overshirt or bomber reads polished, not gym-bound.
Tapered joggers with clean white trainers keep the whole thing looking intentional.
Keep the palette tight — navy, charcoal, black and stone do the heavy lifting. Save the loud kit colours for actual match day.

Brands I'd put next to Castore

If you like what Castore does, here's where else I'd send you across three tiers. Fit notes included, because that's the whole point.

High street

Uniqlo — the best technical basics on the high street, full stop. AIRism and Dry-EX tees are brilliant value and run true to size, so they're a safe layering base under slimmer Castore pieces.
Gymshark — British, and cut with a similar athletic bias, so if Castore fits you well, this will feel familiar. Great for training kit at a friendlier price.
M&S Goodmove — the underrated one. More generous, comfort-led sizing, ideal if you find Castore too snug and want the same smart-casual sportswear look with more room.

Independent & boutique

Represent 247 — Manchester-built premium activewear with a genuinely elevated finish. Fit is slim and considered, very much in Castore's world but with more of a fashion edge.
Vuori — the go-to for premium athleisure that doesn't shout. Softer, slightly more relaxed than Castore, so a good move if you want the quality without the compression fit.

Designer & luxury

Moncler Grenoble — the performance line done at luxury level. Slim, technical, built for the slopes but styled for the street. Sizing runs neat, so try before you commit or size up.
Stone Island — the cult choice for technical outerwear. Cut on the slimmer, boxier side, so a size up gives you that lived-in drape most people are after.
Prada Linea Rossa — proper luxury sportswear with immaculate tailoring. Runs slim and short in the body, very much European fit, so factor that in if you're broad.

Stop guessing your Castore size

Here's the thing about a brand that's "all over the place" on sizing — a standard size chart can only take you so far. It won't tell you that the replica top runs tighter than the training tee, or that the jacket sleeves come up short. That's exactly the gap Tellar.co.uk was built to close.

Tellar is the UK's leading free sizing tool — your body matched exactly to 1,500+ brands instantly. No more squinting at size guides. Here's how it works:

Measure once using your chest, waist and hip — or just plug in a size you already own from another brand. Here's how to measure properly.
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Get your size right the first time, and Castore becomes one of the sharpest things you can put on. Get it wrong, and you'll be posting it back. Measure up, size accordingly, and shop with confidence.

— Marcus Bell, Senior Menswear Stylist, Tellar