Is a 30O the same in every brand?

No - a 30O isn't identical across brands, because brands use different sizing systems and cup depths. Here's how a standard US 30O translates in the brands we track: ThirdLove 30O, Wacoal 30O, Panache 30K, Bravissimo 30K, Freya 30K, Elomi 30K, Glamorise 30O, b.tempt'd 30O, Fantasie 30K. SHEFIT, Kindred Bravely, ENELL size by their own chart instead of band/cup.

What are the sister sizes for 30O?

30O's sister sizes — same cup volume, different band — are 32N. Try a sister size if the band feels too tight or loose but the cup still fits.

30O Bras

What is a 30O in other brands?

42 bras tracked in 30O · 2 brands · See all O cup

Brands: Freya, Panache

Your 30O across brands

A 30O isn’t the same in every brand. Here’s how a standard US 30O translates across the brands we track — and how each one runs.

Brand	How it runs	Your 30O →
ThirdLove	cups run generous	30O
Wacoal	true to size	30O
Panache	true to size	30K
Bravissimo	true to size	30K

What is a 30O in other brands? See all 30+ brands →

Editorial buying guide

Read the 30O buying guide

Top picks, sister sizes, and how to spot a good 30O fit.

Read →

Sister sizes

32N What are sister sizes?

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Your 30O across brands

Kira Active Balcony Swimsuit - Mulberry

Tango Balcony Bra - Nutmeg

Tango Balcony Bra - Navy

Envy Full Cup Bra - Terracotta

Botanical Balcony Bikini Top - Botanical Floral

Tango Balcony Bra - Chai

Botanical Balcony Tankini Top - Botanical Floral

Envy Full Cup Bra - Chai

Envy Full Cup Bra - Chestnut

Envy Full Cup Bra - Teal

Eva Balcony Tankini Top - Sicily Print

Paloma Balcony Swimsuit - Black Sand Print

Paloma Balcony Swimsuit - Capri Print

Paloma Balcony Swimsuit - Navy Gingham

Freya Fancies Balcony Bra (GG - K Cup): White

Freya Fancies Balcony Bra (GG - K Cup): Natural Beige

Freya Fancies Balcony Bra (GG - K Cup): Black

Starlight Side Support Balcony Bra (J - O Cup): Caramel

Starlight Side Support Balcony Bra (J - O Cup): Black

Viva Side Support Bra: Lace Natural Beige

Tango Edit Balcony Bra - White

Anya Riva Spot Balcony Swimsuit - Navy/Vanilla

Offbeat Side Support Bra: Rosehip

Offbeat Side Support Bra: Natural Beige

Offbeat Side Support Bra: Black

Anya Riva Balcony Swimsuit - Black

Tango Balcony Bra - Honey

Tango Balcony Bra - Blush

Tango Balcony Bra - Black

Nina Balcony Bra - Black Leopard

Serene Full Cup Bra - Noir

Serene Full Cup Bra - Vintage

Celeste Balcony Bra - Pistachio

Cora Balcony Bra - Soft Pink

Envy Full Cup Bra - Ivory

Envy Full Cup Bra - Navy

Envy Full Cup Bra - Black

Envy Full Cup Bra - Fuchsia Pink

Envy Full Cup Bra - Honey

Iris Balcony Tankini Top - Black Gingham

Paloma Balcony Swimsuit - Red Gingham

Paloma Balcony Swimsuit - Black Gingham