UK to US conversion

UK 30C in US Bra Size

Convert 30C from UK sizing to US sizing, with the full international table, sister sizes, and practical fit checks in one place.

Instant answer

30C (UK) =

30C US

In this sizing table, 30C in UK sizing converts to 30C in US sizing.

Full conversion table for 30C (US 30C)

30C bra size conversion across US, UK, EU, French, and Australian sizing.
US	UK	EU	FR	AU
30C	30C	65C	80C	8C

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

What this conversion means

Reverse conversions are useful when a tag, retailer, or size chart starts outside the US system. In this table, UK 30C converts to US 30C, then the adjacent links help you compare nearby options.

Sister sizes for the US equivalent (30C)

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

What measurements make a 30C?

The useful way to read 30C is to separate the band from the cup step. In the current calculator formula, the closest starting range is about 29-31 inches (74-79 cm) under the bust and about 32.5-33.5 inches (83-85 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 30C as the US equivalent for those measurement notes.

Is 30C big or small?

Whether 30C feels small, average, or full depends on the body and on the brand. In this size set, the US equivalent uses a smaller band and a middle 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 30C 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 30C differs between brands

30C can shift in feel from one retailer to another because brands grade bands and cups in their own way. 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 30C

30C is easiest to compare when you try shapes that show both cup volume and band tension clearly. 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

Looking for 30C? We may earn a commission if you buy through sponsored links.

Everyday Fit Store

Placeholder for a broad size range and return-friendly basics.

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Comfort Band Co.

Placeholder for supportive everyday styles by band and cup.

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Soft Cup Edit

Placeholder for wire-free and lounge options.

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FAQ

Is 30C the same as 30C in the US?

In this dataset, 30C (UK) converts to 30C 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 30C in Australian sizing?

30C (UK) matches the same base record as 8C (AU). The full table on this page shows each supported label side by side.

How do I check the fit of 30C?

A good US fit should feel secure without digging. If 30C feels close in the cup but wrong in the band, compare the sister sizes before changing cup volume.

What sister sizes work with 30C?

32B are the closest sister-size options for 30C 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 30C?

30C maps to US 30C here. The current calculator formula points to about 29-31 inches underbust and 32.5-33.5 inches bust, or roughly 74-79 cm and 83-85 cm. Treat that as a starting range and then check the real fit.