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Calculate your US bra size from bust and underbust measurements and see equivalent UK and European sizes.
Bra Size Calculation (US):
Band Size = Underbust (in) + 4 (rounded to nearest even number)
Cup Size = Bust - Band Size (each inch = one cup letter)
1 inch difference = A cup, 2 = B, 3 = C, 4 = D, 5 = DD, etc.
Wear a non-padded bra or no bra. Measure your underbust (band size) snugly just below your breasts. Then measure your bust at the fullest point of your chest, keeping the tape parallel to the floor.
Sister sizes are bras with the same cup volume but different band and cup letter combinations. For example, 34C, 36B, and 32D are sister sizes. Going up a band size means going down a cup letter.
Different countries use different measurement systems and size charts. US and UK use inches, while European brands use centimeters. The cup labeling also differs, with UK using E after D and US using DD.
Body size can change with weight fluctuations, pregnancy, hormonal changes, and aging. It is recommended to get re-measured every 1-2 years or whenever you notice your current bra does not fit well.
Signs include the band riding up at the back, straps digging in or slipping, cups wrinkling or overflowing, the center front not lying flat against your chest, or underwire poking or gaping.
The +4 method is a traditional US sizing approach, but many modern fit experts recommend measuring the underbust and using it directly as the band size for a firmer fit. Try both and see which is more comfortable.