What are the sister sizes of 40DD?

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

Is 40DD the same in every brand?

No. A 40DD 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.

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

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

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

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 40DD

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

38DDD 42D

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

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Brands that make DD-cup bras

40DD FAQ

What is 40DD in EU sizing?: 40DD (US) is EU 90E. In UK sizing it is 40DD. 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 40DD?: 38DDD and 42D — same cup volume, different band.
Is 40DD the same in every brand?: No. A 40DD 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.