How to Find Your Sister Bra Size: The Ultimate Sister Sizing Guide
Master sister sizing, then shop your true size. Our buyers rank every bra in your true size in this guide on lift, fit accuracy and how it wears after 30 washes — not on marketing copy. Every pick below is in stock at AngelofYou in sizes XS to 3XL.
step-by-step guide to measuring yourself accurately at home🏆 Editor’s Top Pick
The AngelofYou Padded Push Up Bra — Contour Cups is our best overall bra in your true size for 2026 — the strongest combination of fit accuracy, structure and value in the range.
Shop the top pick →Our Top 3 Picks
What to Look For Before You Buy
- Sister sizes keep identical cup volume while changing the band — 34C equals 32D and 36B.
- If the band rides up, go down a band and up a cup: 36C becomes 34D.
- Cup letters are meaningless without the band number; volume is the band-cup combination.
Frequently Asked Questions
What is bra sister sizing?
Sister sizes are bra sizes with the same cup volume but different band widths. Going down one band size and up one cup size (34C to 32D) keeps the same cup volume.
When should I use a sister size?
When the cup fits but the band is too loose or too tight, or when your exact size is out of stock in a style you want.
Does a 34C equal a 36B?
Yes in cup volume. A 34C, 32D and 36B all hold the same volume; only the band circumference differs.
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