Bra Size Calculator
Calculate bra size based on measurements and sizing charts. Free, fast, accurate — no signup, mobile-friendly, works in
Body Measurements
Current Fit Information
Measuring Tips
- • Measure without a bra or with a non-padded bra
- • Keep the measuring tape parallel to the floor
- • Don't pull the tape too tight - it should be snug but not constricting
- • Take measurements at the end of the day when your body is at its largest
- • Have someone help you measure for better accuracy
Recommended Bra Size
4.0" difference cup volume
Band Size
Around ribcage
Cup Size
Bust projection
Sister Sizes to Try
These sizes have the same cup volume:
Alternative Sizes
Try these if the main size doesn't fit perfectly:
Style Recommendations
- • Try different styles to find what works best for you
- • Ensure the band is snug but comfortable
- • Cups should fully contain breast tissue without gaping
How it works
Bra size combines a band measurement and a cup measurement. The band comes from your snug underbust measurement; the cup comes from the difference between your bust (fullest point) and band — each inch of difference is roughly one cup size.
Band & cup
Band = underbust measurement Cup = bust − band (≈ 1 inch per cup)
- underbust
- snug measure under the bust
- bust
- measure across the fullest point
Worked example
- Underbust = 32 in (band 32)
- Bust = 35 in
- Difference = 35 − 32 = 3 inches
- 3 inches ≈ C cup
Approximately 32C.
Good to know
- Sizing differs between brands and countries, so treat the result as a starting point and try styles on.
- Cup size is relative to the band — a 34B and 36A hold a similar volume (sister sizes).
- A well-fitting band does most of the support work and should sit level and snug.
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Perguntas Frequentes
How do I measure my bra size?
Measure your band size snugly around your ribcage, directly under the bust, and your bust size around the fullest part. The difference between the two determines the cup: roughly one cup size per inch (1" = A, 2" = B, 3" = C, and so on).
What is sister sizing?
Sister sizes share the same cup volume with a different band — a 34C has the same cup capacity as a 36B or a 32D. If a bra fits in the cup but the band is too tight or loose, move to the sister size rather than just changing the cup.
Why does my size differ between brands?
There is no universal sizing standard: brands cut differently, and US, UK, and EU systems label cups differently above D. Treat a calculated size as a starting point and rely on fit checks for each brand.
How do I know a bra fits correctly?
The band should sit level and snug on the loosest hook, the center gore should lie flat against your sternum, and the cups should contain everything without spillage or gaping. The band — not the straps — should provide most of the support.
How often should I re-measure?
Whenever weight changes noticeably, after pregnancy, or about once a year — band and cup needs drift more than most people expect. Bras themselves also stretch with wear, which changes how the same size fits over time.