Bra Conversion Chart: UK to US | Sizing That Fits

UK to US bra sizes share the same band numbers, and cups match through D; above that, UK E becomes US DDD/F and UK F becomes US G.

Bra shopping across the Atlantic gets confusing fast because the two systems agree on bands but split on cups above D. The good news: converting a UK bra size to a US size takes one simple rule and a short cup chart, and the numbers below give you a reliable starting point for ordering from either side. One honest caveat up front — conversion gets you close, not perfect, because every brand cuts its cups slightly differently.

How the UK and US Bra Systems Compare

US and UK bra sizing both measure the underbust in inches, which is why band numbers travel cleanly between the two systems. A UK 34 band is a US 34 band, a UK 36 is a US 36, and so on. The cup letters A through D are also identical in both systems — the systems only start diverging once you get above a D cup.

The chart below shows the most commonly published UK-to-US cup conversion:

If you wear a UK E cup, you’re looking for a US DDD or F depending on the brand; if you wear a UK FF, the US equivalent is an H cup. The higher the cup, the more the letters drift apart, which is exactly where most size-mismatch disasters happen when ordering internationally.

Where Brand Charts Disagree

Retailers don’t all publish the same equivalence table, and that’s not an error — it reflects real differences in how brands cut their patterns. Some US brands use DDD where UK brands use E, and several size charts show overlapping options like DD/E or DDD/F to account for fit overlap between adjacent sizes.

Victoria’s Secret’s UK guide keeps the band number constant and maps UK E to US DDD, while PrimaDonna’s conversion table shows UK E as a US F in some listings. Brastop’s US fitting chart follows the same general ladder but notes that brand-specific sizing can shift the recommended cup by one step. The practical takeaway: use the chart above as your anchor, then check the specific retailer’s conversion table before you order.

What to Watch For When Converting

Three mistakes cause most failed UK-to-US conversions. The first is treating UK DD as US DD in every case — in many charts UK DD maps to the slightly larger US DD/E, and UK E is often the first clearly different step. The second is changing the band when you don’t need to; most UK-to-US charts keep the same band number, so a UK 34F becomes a US 34G, not a US 36G. And the third is assuming one universal chart applies to every brand, which it doesn’t — major retailers publish slightly different equivalence tables for a reason.

Even a perfect conversion is only a starting point. Brand patterns, wire widths, padding, and cup shape all vary by manufacturer, so a converted size that fits one US brand perfectly may run large or small in another. If you’re between sizes or close to a cup boundary, order both adjacent sizes when the return policy allows — and if you’re shopping for a specific full-bust size, our tested roundup of the best 34H bras covers the top picks worth trying first.

FAQs

Is UK and US bra band size the same?

Yes, band numbers are identical between the UK and US systems because both measure the underbust in inches. A UK 34 band matches a US 34 band exactly, and this holds for every band size. Only the EU and AU systems use different numbering for bands.

What is a UK 34E in US size?

A UK 34E converts to a US 34DDD or sometimes a US 34F, depending on the brand. The band stays at 34 in both systems. Because some US brands label this size differently, checking the retailer’s own conversion chart before ordering is worth the extra minute.

Why do US and UK cup sizes differ above D?

The two systems evolved separately to label the same physical volumes. UK sizing uses single letters like E, F, and FF, while US sizing adds extra D letters like DDD before moving to single letters such as G and H. Both systems describe the same cup volume, just with different names.