Bra Size Chart – Band & Cup Size Conversion Guide
Get a full breakdown of band and cup equivalence tables and learn to decode sizes across US, UK, EU, and more.
Read more →Sister Size Finder
Not sure if your current bra fits just right? Discover your sister sizes instantly! Enter your current band and cup to see alternative sizes that offer the same cup volume in a slightly different fit.
Find Your Sister Sizes
Try These Sister Sizes:
Smaller Band / Larger Cup
Tighter band, more lift
Larger Band / Smaller Cup
Looser band, relaxed fit
Sister sizes have the same cup volume as your original size but with a different band.
Sister Size Reference Table
| Original Size | Smaller Band / Larger Cup | Larger Band / Smaller Cup |
|---|---|---|
What is Sister Sizing?
Sister sizing is a fitting technique that helps you find alternate bra sizes with the same cup volume but a different band. If your usual size is slightly uncomfortable, or a better fit is needed, a sister size may be the answer.
- A smaller band + larger cup (e.g. 30DD) offers more lift, but a tighter feel.
- A larger band + smaller cup (e.g. 34C) can feel more relaxed, but gives a looser band.
- Sister sizes work because each diagonal move (up band/down cup or down band/up cup) keeps the cup volume approximately the same.
- This can help when you can't find your usual size in stock, or your fit needs fine-tuning.
Frequently Asked Questions
If your cups fit but the band is too tight/loose, or if you can't find your usual size in stock, use a sister size for a similar cup volume but a more comfortable band.
The cup volume will be very close. However, the shape and fit may change slightly based on band size, breast shape, and brand.
Most brands follow this system, but slight variations may exist. Always check fit and comfort above all!
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