What Is Sizing Like at Uniqlo? Your No-Nonsense Guide

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

Uniqlo sizes run small compared to UK high street sizing — as a general rule, you'll want to go up one, sometimes two sizes from what you'd usually buy, and the brand's Japanese origins mean the cut is narrower through the shoulders and hips than most British women are used to. That said, once you crack the sizing code? Uniqlo is genuinely one of the best investments in your wardrobe. I say that as someone who's bought at least forty things from them over the years, with a ratio of brilliant wins to "what was I thinking" moments firmly in favour of the former.

The key is knowing what runs small, what's more forgiving, and when to just size up without overthinking it. Let me walk you through it.

Why Does Uniqlo Run Small?

Uniqlo is Japanese, and Japanese sizing is graded to a narrower, more petite frame than UK or European standard. The label says "M" but it's not a UK M — it's cut closer to a UK 10 or sometimes a tight 12. This trips people up constantly, particularly with fitted pieces like the Heattech tops, Oxford shirts, and their ultra-popular cashmere knitwear range.

The good news: Uniqlo's sizing is consistent. Once you know your Uniqlo size, you can pretty much bank on it across seasons — which is more than you can say for a lot of brands.

Uniqlo Size Conversion Guide (Women's)

Here's a straightforward reference chart to get you started. I always recommend checking the specific measurements on the product page too, because cut can vary across different lines.

Uniqlo LabelUK SizeEU SizeUS SizeBust (cm)Waist (cm)Hips (cm)XS6–834–362–480–8462–6688–92S8–1036–384–684–8866–7092–96M10–1238–408–1088–9270–7496–100L12–1440–4210–1292–9674–78100–104XL14–1642–4412–1496–10078–82104–108XXL16–1844–4614–16100–10882–90108–1163XL18–2046–4816–18108–11690–98116–124

Note: These are general guidelines. Always cross-reference with the specific garment measurements on the Uniqlo website — their knitwear, outerwear, and denim each have their own quirks.

Sizing by Garment Type

This is where it gets interesting — and honestly, where most people go wrong. Uniqlo isn't uniform across categories. Here's my honest breakdown:

Heattech Tops & Base Layers: These are designed to be close-fitting, and they are. I'm usually a UK 10–12 and wear a Medium with no issues, but if you have any width across the shoulders or a fuller bust, go straight to Large. Don't wrestle with it.
Knitwear & Cashmere Jumpers: Uniqlo's cashmere is a brilliant buy — I own three in rotation — but size up by one. A Medium is more of a neat UK 10. If you want any ease or prefer an oversized fit (which works beautifully with their straight-leg trousers), go up two.
Oxford & Smart Shirts: These are cut narrow. The shoulder seam in particular sits quite close. I'd advise trying before you buy if possible, or going up a size. Petite women often find the standard lengths too long — the XS or S can work well here.
Trousers & Skirts: More forgiving than the tops. The wide-leg and straight-cut trousers tend to have a bit more room. Sizing is generally consistent with the chart above. The ankle-length cuts are genuinely flattering on taller frames too.
Outerwear & Puffer Jackets: Size up, every time. The puffer coats — particularly the beloved Ultra Light Down range — are designed to layer over other clothes. Even their longer oversized styles feel snug on a UK 12 if you stay true to size. Go L or XL for comfort and movement.
Denim: Uniqlo jeans are slim through the thigh and sit high — perfect for some bodies, uncomfortable for others. If you carry more volume through the hips or thighs, go up a size and belt at the waist.
Loungewear & Pyjamas: These are actually more generous. I've found these run fairly true to UK size, sometimes even slightly roomy — ideal if you want that relaxed fit without sizing up.

My Tips for Shopping Uniqlo Without the Headache

Check your measurements, not just your usual size. Uniqlo lists detailed measurements on every product — bust, waist, hips, and length. Use them. It takes 30 seconds and saves a return.
If you're between sizes, go up. Unlike some brands where a size too large looks sloppy, Uniqlo's clean-cut basics actually look great with a touch of ease. It's part of the aesthetic.
Petite shoppers tend to do well. If you're under 5'4", Uniqlo's proportions often suit you beautifully without alterations — the lengths, sleeve widths, and narrower cuts are closer to a petite fit.
Taller or broader women: Go up two sizes or use the brand's size chart carefully. The XL and XXL options are there, but the silhouettes are still cut for a narrower frame, so fit can feel restrictive.

Brands With a Similar Sizing Feel to Uniqlo

If you're buying basics and want a similar fit philosophy — minimal, well-cut, consistent — here are brands I'd point you towards, split by budget:

High Street:

COS — Sister brand to H&M but elevated. Sizing is similarly European-lean, with that same clean architectural cut. A brilliant alternative for structured basics.
Massimo Dutti — Sizes slightly more generously than Uniqlo but has a comparable quality-meets-minimalism ethos. Their knitwear is outstanding value.
Mango — Runs slightly small like Uniqlo, especially in fitted styles. Great for transitional-season layering pieces.
M&S — Unsung hero of the high street for basics. Trousers and knitwear in particular are excellent, and UK sizing tends to be more true-to-size than Uniqlo.
The White Company — If you love Uniqlo's clean palette and quality basics focus, The White Company is a natural move up. Sizing is generous and consistent.
Hush — A great mid-market pick for easy, relaxed basics with a similar low-key aesthetic to Uniqlo. Very true to UK size.
Me&Em — A step up in price but superb quality for everyday tailored basics. Sizing is UK-standard and consistent season to season.
Boden — A stalwart for classic basics. Their knitwear competes directly with Uniqlo's cashmere range at a similar price point, with a more typically British fit.

Two Independent Picks Worth Knowing:

Sunspel — A British heritage brand making some of the best quality basics in the country. Their fitted tees and knits are exceptional. Sizing is narrow like Uniqlo, but the craftsmanship is worth every penny.
Community Clothing — Patrick Grant's ethical UK-made basics brand. Think sustainably produced, true-to-size everyday staples with genuinely good quality at a fair price. A brilliant find if you haven't stumbled across them yet.

Never Guess Your Size Again — Use Tellar

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Plus, the Tellar Fashion Hub is a free library of honest, unsponsored style advice from our top stylists. No affiliate bias. No brand deals. Just straight-talking fashion guidance.