UK vs USA Sizing Difference - Find Your Size with Tellar.co.uk

UK sizing runs approximately two sizes smaller than USA sizing for womenswear, meaning a UK size 12 equals a US size 8, whilst shoes differ by about 2-2.5 sizes with a UK 5 being a US 7.5. I've spent years helping clients navigate this confusing transatlantic sizing minefield, and trust me, getting it wrong means disappointment at the doorstep and tedious returns.

Shopping internationally used to mean guesswork and crossed fingers. Now, with online shopping dominating our wardrobes, understanding the UK versus USA sizing split isn't just helpful—it's essential. Whether you're eyeing that perfect pair of jeans from an American brand or treating yourself to British heritage pieces, I'm breaking down everything you need to know.

The Sizing Basics: What You Need to Know

The fundamental difference stems from completely separate sizing systems developed decades apart. UK sizes typically run 10, 12, 14, 16, whilst US sizes go 6, 8, 10, 12 for the same measurements. It's not a direct science though—vanity sizing has muddied the waters considerably, with some brands sizing up or down to flatter their target customer.

Here's what genuinely matters: a UK 8 translates to a US 4, a UK 10 to a US 6, a UK 12 to a US 8, and a UK 14 to a US 10. But—and this is crucial—measurements trump size labels every single time. I've seen a UK 12 fit identically to a US 10 in one brand and a US 6 in another. Maddening, isn't it?

Clothing Categories: The Detail That Matters

Dresses and tops follow the standard two-size difference, but here's where it gets interesting. Zara, one of the most globally shopped high street brands, uses European sizing that differs from both UK and US—their size 38 equals a UK 10 and US 6. Mango follows similar European conventions, so always check their specific size guides. H&M offers brilliant size consistency across regions, making them reliable for international ordering.

Jeans present their own particular challenge. Whilst numbered sizing (like 26, 27, 28) offers more consistency, lettered sizes (XS, S, M, L) vary wildly. Levi's, the denim authority, uses waist measurements in inches, which works universally—but their fits vary significantly between vintage, classic, and modern cuts. Citizens of Humanity and Paige both use numerical sizing that translates fairly accurately between markets, though I'd always size up if you're between measurements.

Footwear: A Different Beast Entirely

Shoes require separate attention. UK sizing sits roughly 2 to 2.5 sizes below US sizing. A UK 5 equals a US 7 or 7.5, a UK 6 equals a US 8 or 8.5, and so forth. All Saints boots run notoriously narrow in their UK sizing, whilst Kurt Geiger, a beloved British footwear brand, offers generous width fittings that translate beautifully across sizing systems. Vagabond Shoemakers, a brilliant Scandinavian independent, uses European sizing (36, 37, 38) that requires conversion for both UK and US customers—but their quality justifies the extra effort.

High Street Heroes for International Shopping

COS offers minimal, architectural pieces with excellent size consistency across their global stores. Their size guides are accurate, and their quality justifies the investment.

Whistles brings contemporary British style with reliable sizing that holds true whether you're ordering from London or Los Angeles. Their tailoring runs true to size.

Jigsaw provides sophisticated wardrobe essentials with detailed measurements on every product page. Their customer service team are exceptional at sizing queries.

Reiss delivers premium high street fashion with sizing that tends slightly fitted. Consider sizing up in their structured pieces like blazers and coats.

French Connection offers fashion-forward pieces with generous sizing—I often advise clients to take their usual size or even size down in knitwear.

Me&Em creates beautifully cut casualwear that's worth the investment. Their sizing runs true, and they provide comprehensive measurement guides.

Hobbs specialises in workwear and occasion dressing with classic British tailoring. Their sizing is consistent and true to measurements.

Premium and Designer Options

Max Mara represents Italian luxury with sophisticated tailoring. They use Italian sizing (typically 40, 42, 44), which requires conversion, but their in-store staff and website provide excellent guidance.

Claudie Pierlot, a chic French contemporary brand, offers Parisian style with European sizing. Their pieces run slightly fitted, perfect for that effortlessly elegant aesthetic.

The Bra Situation: Utterly Different

Bra sizing deserves special mention because it's genuinely confusing. UK bras use inches for band sizes (32, 34, 36) with cup letters progressing logically (A, B, C, D, DD, E, F). US sizing also uses inches for bands but diverges on cups—they use DDD instead of E, and their progression differs beyond D cup. M&S, Britain's lingerie authority, offers exceptional fit expertise with detailed guides for international customers. Bravissimo, an independent British brand specialising in D-cup and above, provides outstanding fitting advice and ships internationally with clear size conversions.

My Professional Tips for Getting It Right

Firstly, always measure yourself properly. You need bust, waist, and hip measurements in both inches and centimetres. Update these every six months because bodies change. Secondly, read reviews obsessively—customers will flag if items run large, small, or true to size. Asos excels at this with their customer photo feature and detailed reviews that specify height and size ordered.

Check return policies before international orders. Boden offers free returns from the US, making them risk-free for American customers wanting British style. Anthropologie ships internationally with reasonable return windows, though return postage varies.

Consider brands that use measurements instead of sizes. Toast, a gorgeous independent British brand, provides detailed garment measurements, letting you compare directly with pieces you already own. The Fold, another brilliant independent specialising in workwear, offers exceptional measurement guides and personal styling advice.

Introducing Tellar.co.uk: Your Sizing Solution

Here's where the frustration ends and the solution begins. Tellar.co.uk is the UK's leading sizing tool that eliminates guesswork entirely. You measure once using your bust, waist, and hip measurements, or input your existing brand size, and Tellar matches your body exactly to over 1,500 brands instantly. Never look at a confusing size guide again.

Their Store Size Lookup tool gives you your precise size in any brand—whether that's COS, Reiss, or American favourites. It's completely free, works directly in your browser without downloads, and genuinely revolutionises how you shop internationally.

Plus, there's the Tellar Fashion Hub—a library stacked with free posts from top stylists covering every fashion query imaginable. Honest, unbiased, independent, and always free. You'll find style advice, top picks, and brand recommendations including The Ultimate Clothing Sizing Guide, Jeans Trends 2026, The Ultimate Guide to Dresses, and The Ultimate Guide to Jackets.

Shopping internationally shouldn't mean returns, disappointment, or wasted money. With proper measurements, smart brand choices, and tools like Tellar, you can confidently order from anywhere in the world knowing your size will be spot-on. Happy shopping!