What are the sister sizes of 40C?

38D and 42B — same cup volume, different band.

Is 40C the same in every brand?

No. A 40C can fit differently between brands because of pattern, fabric and cup shape. Use it as a starting point and try a sister size when switching brands.

40C bra size — conversion chart, sister sizes & brands

A 40C bra (US notation) in every regional standard. The same band-and-cup, labelled eight different ways.

US	UK	EU	FR	IT	AU	JP	IN
40C	40C	90C	105C	90C	18C	90C	40C

Band conversions are exact; cup fit still varies by brand, style, and body — a conversion is a starting point, not a guarantee.

Sister sizes of 40C

Sister sizes hold the same cup volume with a different band — the quickest fix when a band feels too tight or too loose.

38D 42B

Not sure you're a 40C? Two measurements, two minutes — free, nothing stored.

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Brands that make C-cup bras

40C FAQ

What is 40C in EU sizing?: 40C (US) is EU 90C. In UK sizing it is 40C. Band conversions are exact; cup fit still varies by brand, style, and body — a conversion is a starting point, not a guarantee.
What are the sister sizes of 40C?: 38D and 42B — same cup volume, different band.
Is 40C the same in every brand?: No. A 40C can fit differently between brands because of pattern, fabric and cup shape. Use it as a starting point and try a sister size when switching brands.