Bra Size Calculator
Find your US, UK, and EU bra size from your underbust and bust measurements, plus sister sizes for a better fit.
Your measurements
Enter your underbust and bust measurements. Bust must be larger than underbust.
Frequently Asked Questions about the Bra Size Calculator
How do I measure for a bra size?
Wrap a soft tape snug around your ribcage directly under your bust for the underbust (band). Then measure loosely across the fullest part of your bust, keeping the tape level front to back. Enter both numbers above.
What are sister sizes?
Sister sizes share the same cup volume but use a different band. If your band feels too tight, go up one band and down one cup (for example, 34C to 36B). If it feels loose, go down one band and up one cup (34C to 32D).
Why does the same size fit differently across brands?
Brands cut bands, wires, and cups to different blocks, and fabrics stretch differently. Two bras labeled 34C from different makers can fit a full cup size apart. Always try several brands before settling on one.
What if I am between sizes?
If your bust measurement falls on the half inch, try the smaller cup first because most bands stretch slightly with wear. If the band rides up at the back, go down a band and up a cup using the sister-size rule.
Why does my US size not match my EU size in numbers?
US and UK bands use inches (32, 34, 36), while EU bands use centimeters of underbust (70, 75, 80). Cup letters also diverge above D, so a US 34DD maps to a UK 34DD but an EU 75E.
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