UK to US conversion

UK 34DD in US Bra Size

Convert 34DD from UK sizing to US sizing, with the full international table, sister sizes, and practical fit checks in one place.

Instant answer

34DD (UK) =

34DD US

In this sizing table, 34DD in UK sizing converts to 34DD in US sizing.

Full conversion table for 34DD (US 34DD)

34DD bra size conversion across US, UK, EU, French, and Australian sizing.
US	UK	EU	FR	AU
34DD	34DD	75E	90E	12DD

Bra sizing varies between brands. Use this as an accurate starting point and check the fit.

What this conversion means

UK sizing can look unfamiliar because the band and cup sequences are not always written like US labels. For 34DD, this shared data file maps the fit target to 34DD in US sizing.

Sister sizes for the US equivalent (34DD)

Sister sizes: 32DDD and 36D can be worth checking when the cup volume feels close but the band needs a different feel.

What measurements make a 34DD?

A size like 34DD makes more sense when the two tape measurements are shown side by side. In the current calculator formula, the closest starting range is about 33-35 inches (84-89 cm) under the bust and about 38.5-39.5 inches (98-100 cm) around the fullest part of the bust. The band comes from the underbust rounding, while the cup step comes from the difference between bust and band. This page uses 34DD as the US equivalent for those measurement notes.

Is 34DD big or small?

34DD should be treated as a fit label, not as a judgement about body size. In this size set, the US equivalent uses a middle band and a fuller cup step. Cup letters are relative to the band, so a D on one band is not the same volume as a D on every other band. The most useful question is whether the band stays level and the cups hold smoothly, not whether the label sounds large or small.

If 34DD doesn't fit right

Band rides up: The band may be too loose or stretched out; try a snugger band or compare the snugger sister size.

Cups gape: The cup may be too roomy, too deep, or pulled away by a loose band; check the band before changing cup volume.

Cups spill: The cup volume may be too small or the cup shape may be too closed; try one cup step up before changing the band.

Straps dig in: The straps may be compensating for a band that is not supporting enough; reset the band fit before tightening straps.

How 34DD differs between brands

Use 34DD as the starting label, then let the individual brand chart narrow the choice. A firmer elastic can make the same band feel smaller, and a shallow or narrow cup can make the same cup letter feel different. Check the retailer chart, read fit notes when available, and compare the label against the brand and region sizing guide before treating the conversion as final.

Shopping for 34DD

Treat 34DD as your anchor size while you compare cup shape, strap placement, and band feel. If the cup is in a lower or middle step, lightly lined T-shirt styles can make gaps easy to spot. Fuller cup steps often benefit from styles with steadier side support, deeper cups, or a balconette shape depending on breast shape. For special outfits, compare the fit needs in the outfit guides before choosing a strapless, plunge, or backless option.

Bras in your size

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Everyday Fit Store

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Comfort Band Co.

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Soft Cup Edit

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FAQ

Is 34DD the same as 34DD in the US?

In this dataset, 34DD (UK) converts to 34DD in US sizing. Some brands publish their own charts, so use this as the closest standard label and still check the real fit.

What is 34DD in Australian sizing?

34DD (UK) matches the same base record as 12DD (AU). The full table on this page shows each supported label side by side.

How do I check the fit of 34DD?

A good US fit should feel secure without digging. If 34DD feels close in the cup but wrong in the band, compare the sister sizes before changing cup volume.

What sister sizes work with 34DD?

32DDD and 36D are the closest sister-size options for 34DD in this dataset. Try a sister size when cup volume feels close but the band needs to feel snugger or looser.

Why do bra sizes differ between countries?

Bra labels are written differently across US, UK, EU, French, and Australian systems. Cup letters can also diverge after D, so a converted label is a starting point rather than a promise of identical fit.

What measurements usually make 34DD?

34DD maps to US 34DD here. The current calculator formula points to about 33-35 inches underbust and 38.5-39.5 inches bust, or roughly 84-89 cm and 98-100 cm. Treat that as a starting range and then check the real fit.