What is a bra size calculator?
A bra size calculator estimates band and cup size from your underbust and bust measurements, then gives sister sizes that may fit similarly.
Free ecommerce tools
Free Bra Size Calculator
A bra size calculator estimates your band and cup size from underbust and bust measurements, then shows nearby sister sizes and fit notes to make online shopping easier.
Inches or centimeters
Sister size comparison
Copyable fit notes
Estimated starting size
32D
32D uses a 4 inch bust difference after band rounding.
Band
32
Cup
D
Sister sizes
30DD/E34C
Bra size calculator questions
How do I measure for a bra size?
Measure snugly around the rib cage under the bust for band size, then measure around the fullest part of the bust while keeping the tape level.
Are bra size calculators exact?
No calculator is exact because brands, cup shape, wire width, fabric stretch, and body shape all affect fit. Use the result as a starting point.
What are sister sizes?
Sister sizes are nearby band and cup combinations with similar cup volume, such as 32D, 30DD/E, and 34C.
Should I size up or down if a bra feels uncomfortable?
If the band rides up, try a smaller band and larger cup. If cups overflow, try a larger cup. If wires dig into breast tissue, try a wider cup shape.
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