Size conversion
What Is a 30I in Other Brands?
Bra sizes are not standardized: the same label means different things brand to brand, so your 30I is a starting point, not a fixed size. A US 30I usually needs a 30J in Victoria’s Secret, maps to a 30G in a true-to-size UK brand like Panache, and stays a 30I in Wacoal.
Your 30I in Victoria's Secret
30J
Cups run a full cup small, so size up
Your 30I in Panache
30G
True-to-size UK sizing
Your 30I in Wacoal
30I
True to size, year after year
Every brand we track
Your 30I, 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 30I → |
|---|---|---|
| ThirdLovein stock | cups run generous | 30I |
| Wacoalin stock | true to size | 30I |
| Glamorisein stock | true to size | 30I |
| SHEFITin stock | - | Adjustable XS-6Luxe sizing rather than standard band/cup; size by the brand chart. |
| b.tempt'din stock | true to size | 30I |
| 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 | 30I |
| Bali | band runs large | 28I |
| Playtex | band runs large | 28I |
| Maidenform | true to size | 30I |
| Vanity Fair | band runs large | 30I |
| Calvin Klein | band runs small | 30I |
| Victoria's Secret | cups run small | 30J |
| Brooks | band runs small | 30I |
| 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 | 30I |
| Torrid | band runs large | 30I |
UK
UK-sized brands (cups run D, DD, E, F, FF, G...)
EU
EU-sized brands
| Brand | How it runs | Your 30I → |
|---|---|---|
| Chantelle | cups run small | 30I |
| Simone Perele | cups run small | 30I |
| PrimaDonna | true to size | 30I |
| Marie Jo | true to size | 30I |
| Triumph | band runs large | 30I |
| Anita | true to size | 30I |
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 30I now
Real bras we track in stock in 30I, with live prices.
Freya
Offbeat Padded Half Cup Bra: Black
$66.00View →
Freya
Offbeat Plunge Bra: Rosehip
$66.00View →
Freya
Offbeat Side Support Bra: Rosehip
$68.00View →
Freya
Offbeat Molded Bra: Rosehip
$70.00View →
Freya
Starlight Side Support Balcony Bra: Caramel
$66.00View →
Freya
Starlight Side Support Balcony Bra: Black
$66.00View →
Freya
Starlight Molded Bra: Rosewater
$72.00View →
Freya
Starlight Molded Bra: Caramel
$72.00View →
30I sister sizes
Sister sizes hold the same cup volume on a different band. If the 30I cup fits but the band doesn’t, try:
Interactive
Try your own size
Not a 30I? Enter any size to see it in every brand. Your size never leaves your browser.
Brand Size Translator
Find your size across different brands
30I
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.
30I
Wacoal
US
True to size; consistent fit across decades.
30I
Panache
UK
UK sizing; true to size, consistent year over year.
30G
Freya
UK
UK sizing; bands run snug.
30G
Elomi
UK
UK plus-size full-bust; cups run generous.
30G
Glamorise
US
US full-figure; true to size.
30I
SHEFIT
US
Adjustable XS-6Luxe sizing rather than standard band/cup; size by the brand chart.
30I
b.tempt'd
US
Wacoal-family fit DNA; runs true to US sizing, lighter construction.
30I
Kindred Bravely
US
Uses XS-XXL nursing/maternity sizing rather than band/cup; size by the brand chart.
30I
ENELL
US
Uses numeric high-impact sizing (00-8) rather than band/cup; size by the brand chart.
30I
Natori
US
Cups run small; consider sizing up.
30I
Chantelle
EU
French sizing; cups run small.
30I
Bali
US
Bands run loose; consider sizing down.
28I
Playtex
US
Bands run large; size down in band.
28I
Maidenform
US
Generally true to size.
30I
Vanity Fair
US
Bands run slightly loose.
30I
Calvin Klein
US
Bands run slightly snug.
30I
Victoria's Secret
US
Cups run very small; size up a full cup.
30J
Fantasie
UK
UK sizing; consistent fit.
30G
Curvy Kate
UK
UK sizing; bands run firm.
30G
Gossard
UK
UK sizing; classic fit.
30G
Pour Moi
UK
UK sizing; budget-friendly.
30G
Simone Perele
EU
French luxury; cups run small.
30I
PrimaDonna
EU
Belgian luxury; true EU sizing.
30I
Marie Jo
EU
Belgian; consistent fit.
30I
Triumph
EU
German; bands slightly generous.
30I
Anita
EU
German; strong post-surgery range.
30I
Brooks
US
Compression sports style; may run snug.
30I
Under Armour
US
Compression fit runs generous; XS-XL sizing rather than band/cup; size by the brand chart.
30I
Nike
US
Generous fit; XS-XL sizing rather than band/cup; size by the brand chart.
30I
Goddess
UK
UK sizing; strong plus-size range.
30G
Cacique
US
Lane Bryant's brand; bands run generous.
30I
Torrid
US
Plus-focused; bands run large.
30I
Common questions
30I conversion questions
- What is a 30I in Victoria's Secret?
- Victoria's Secret cups run about a full cup small, so a standard US 30I usually needs a 30J there. If you already wear a 30I in Victoria's Secret, your size in a true-to-size brand is likely a cup smaller.
- Which brands keep a 30I the same?
- In true-to-size brands a US 30I stays a 30I: 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 30I 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 30I is a 30G; the band number stays the same.
- What size replaces a 30I 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 30I doesn't carry over directly. Start from each brand's chart with your underbust and bust measurements.