Size conversion
What Is a 30O in Other Brands?
Bra sizes are not standardized: the same label means different things brand to brand, so your 30O is a starting point, not a fixed size. A US 30O usually needs a 30AA in Victoria’s Secret, maps to a 30AA in a true-to-size UK brand like Panache, and stays a 30AA in Wacoal.
Your 30O in Victoria's Secret
30AA
Cups run a full cup small, so size up
Your 30O in Panache
30AA
True-to-size UK sizing
Your 30O in Wacoal
30AA
True to size, year after year
Every brand we track
Your 30O, brand by brand
Grouped by the sizing system each brand labels its cups in. Brands we stock link to their full lineup.
US
US-sized brands
| Brand | How it runs | Your 30O → |
|---|---|---|
| ThirdLovein stock | cups run generous | 30AA |
| Wacoalin stock | true to size | 30AA |
| Glamorisein stock | true to size | 30AA |
| SHEFITin stock | - | Adjustable XS-6Luxe sizing rather than standard band/cup; size by the brand chart. |
| b.tempt'din stock | true to size | 30AA |
| Kindred Bravelyin stock | - | Uses XS-XXL nursing/maternity sizing rather than band/cup; size by the brand chart. |
| ENELLin stock | - | Uses numeric high-impact sizing (00-8) rather than band/cup; size by the brand chart. |
| Natori | cups run small | 30AA |
| Bali | band runs large | 28AA |
| Playtex | band runs large | 28AA |
| Maidenform | true to size | 30AA |
| Vanity Fair | band runs large | 30AA |
| Calvin Klein | band runs small | 30AA |
| Victoria's Secret | cups run small | 30AA |
| Brooks | band runs small | 30AA |
| Under Armour | - | Compression fit runs generous; XS-XL sizing rather than band/cup; size by the brand chart. |
| Nike | - | Generous fit; XS-XL sizing rather than band/cup; size by the brand chart. |
| Cacique | band runs large | 30AA |
| Torrid | band runs large | 30AA |
UK
UK-sized brands (cups run D, DD, E, F, FF, G...)
EU
EU-sized brands
| Brand | How it runs | Your 30O → |
|---|---|---|
| Chantelle | cups run small | 30AA |
| Simone Perele | cups run small | 30AA |
| PrimaDonna | true to size | 30AA |
| Marie Jo | true to size | 30AA |
| Triumph | band runs large | 30AA |
| Anita | true to size | 30AA |
Translations are guidance from cross-brand fit data, not a guarantee - fit also depends on breast shape and style. Cross-brand offset data v1-2026-05-28.
In stock now
Shop 30O now
Real bras we track in stock in 30O, with live prices.
Freya
Offbeat Side Support Bra: Rosehip
$68.00View →
Freya
Starlight Side Support Balcony Bra (J - O Cup): Caramel
$66.00View →
Freya
Starlight Side Support Balcony Bra (J - O Cup): Black
$66.00View →
Freya
Viva Side Support Bra: Lace Natural Beige
$66.00View →
Freya
Offbeat Side Support Bra: Natural Beige
$68.00View →
Freya
Offbeat Side Support Bra: Black
$68.00View →
Freya
Freya Fancies Balcony Bra (GG - K Cup): White
$64.00View →
Freya
Freya Fancies Balcony Bra (GG - K Cup): Natural Beige
$64.00View →
30O sister sizes
Sister sizes hold the same cup volume on a different band. If the 30O cup fits but the band doesn’t, try:
Interactive
Try your own size
Not a 30O? Enter any size to see it in every brand. Your size never leaves your browser.
Brand Size Translator
Find your size across different brands
30O
Why sizes vary: Each brand uses different patterns, materials, and fit philosophies. A 34DD in Victoria's Secret fits differently than a 34DD in Panache.
ThirdLove
US
Half-cup sizing available; cups run slightly generous.
30AA
Wacoal
US
True to size; consistent fit across decades.
30AA
Panache
UK
UK sizing; true to size, consistent year over year.
30AA
Freya
UK
UK sizing; bands run snug.
30AA
Elomi
UK
UK plus-size full-bust; cups run generous.
30AA
Glamorise
US
US full-figure; true to size.
30AA
SHEFIT
US
Adjustable XS-6Luxe sizing rather than standard band/cup; size by the brand chart.
30AA
b.tempt'd
US
Wacoal-family fit DNA; runs true to US sizing, lighter construction.
30AA
Kindred Bravely
US
Uses XS-XXL nursing/maternity sizing rather than band/cup; size by the brand chart.
30AA
ENELL
US
Uses numeric high-impact sizing (00-8) rather than band/cup; size by the brand chart.
30AA
Natori
US
Cups run small; consider sizing up.
30AA
Chantelle
EU
French sizing; cups run small.
30AA
Bali
US
Bands run loose; consider sizing down.
28AA
Playtex
US
Bands run large; size down in band.
28AA
Maidenform
US
Generally true to size.
30AA
Vanity Fair
US
Bands run slightly loose.
30AA
Calvin Klein
US
Bands run slightly snug.
30AA
Victoria's Secret
US
Cups run very small; size up a full cup.
30AA
Fantasie
UK
UK sizing; consistent fit.
30AA
Curvy Kate
UK
UK sizing; bands run firm.
30AA
Gossard
UK
UK sizing; classic fit.
30AA
Pour Moi
UK
UK sizing; budget-friendly.
30AA
Simone Perele
EU
French luxury; cups run small.
30AA
PrimaDonna
EU
Belgian luxury; true EU sizing.
30AA
Marie Jo
EU
Belgian; consistent fit.
30AA
Triumph
EU
German; bands slightly generous.
30AA
Anita
EU
German; strong post-surgery range.
30AA
Brooks
US
Compression sports style; may run snug.
30AA
Under Armour
US
Compression fit runs generous; XS-XL sizing rather than band/cup; size by the brand chart.
30AA
Nike
US
Generous fit; XS-XL sizing rather than band/cup; size by the brand chart.
30AA
Goddess
UK
UK sizing; strong plus-size range.
30AA
Cacique
US
Lane Bryant's brand; bands run generous.
30AA
Torrid
US
Plus-focused; bands run large.
30AA
Common questions
30O conversion questions
- What is a 30O in Victoria's Secret?
- Victoria's Secret cups run about a full cup small, so a standard US 30O usually needs a 30AA there. If you already wear a 30O in Victoria's Secret, your size in a true-to-size brand is likely a cup smaller.
- Which brands keep a 30O the same?
- In true-to-size brands a US 30O stays a 30O: Wacoal, Panache, Glamorise, b.tempt'd, Maidenform, Fantasie, Gossard, Pour Moi, PrimaDonna, Marie Jo, Anita, Goddess. Fit can still vary by style, so treat the label as the starting point.
- Do UK brands size a 30O differently from US brands?
- UK brands label cups in a different sequence above D (D, DD, E, F, FF, G), so the same letters can mean different volumes. In a true-to-size UK brand like Panache, a US 30O is a 30AA; the band number stays the same.
- What size replaces a 30O in brands that don't use cup sizes?
- SHEFIT, Kindred Bravely, ENELL, Under Armour, Nike size by their own charts (XS-XL or numeric) instead of band/cup, so a 30O doesn't carry over directly. Start from each brand's chart with your underbust and bust measurements.