Bra Size Calculator
This tool estimates a bra size from two soft-tape measurements: your ribcage (underbust) and your bust at the fullest point. It is a starting point only—fit still depends on brand, style, and personal comfort.
- Wear a lightly lined or unpadded bra, or measure over a thin top.
- Keep the tape level and snug for underbust; do not squeeze the ribs.
- For bust, measure around the fullest part, usually across the nipples, without indenting the skin.
- Bust must be a bit larger than underbust, or we cannot estimate a cup size.
Units
Measure directly under your bust, where the band sits, after a normal exhale.
Measure around the fullest part of your bust while standing straight.
We still show every region below; this choice highlights the row that matters most when you shop.
Your suggested size (US / Canada)
28G
Common on tags sold in the United States and Canada. If you shop mostly in North America, use this column when comparing brands.
All regional labels (same estimate)
Retailers use different lettering and band scales. Use the column that matches the country shown on the product page.
US / Canada · highlighted
28G
Common on tags sold in the United States and Canada. If you shop mostly in North America, use this column when comparing brands.
United Kingdom
28G
Widely used by UK lingerie brands. Cup letters follow UK rules; the same bust volume may not use identical letters as a US tag.
European band
70 G
Band is often labelled with an underbust length in centimetres, rounded (for example 70, 75, 80). Cup letter follows beside it.
Australia / NZ
28G
Many AU/NZ charts align closely with UK cup letters. Always confirm on the retailer’s own size chart—labelling differs by brand.
What this does not replace: trying bras on, sister sizes (same cup volume on a different band), or advice from a professional fitter. If bands ride up or cups gape, the label size may need adjusting even when measurements match.
Related tools
Shopping for clothes internationally? Use the dress size converter for bust, waist, and hip in US, UK, and EU dress labels. For general body composition context, see the body fat estimator (separate from bra fit).
Important usage notes & limitations
Reproductive timelines interact with contraception cessation, PCOS phenotype, transgender hormone therapy intensity, low body-fat athletic amenorrhea, and perimenopause. Hormonal contraception intentionally suppresses natural ovulatory signals until washout stabilization — calendar methods become meaningful only once cycles resume reliably.
See also: Pregnancy Due Date Calculator · Women's health calculators hub.