Is a 40O the same in every brand?

No — a 40O isn't identical across brands, because brands use different sizing systems and cup depths. Here's how a standard US 40O translates in the brands we track: ThirdLove 40AA, Wacoal 40AA, Panache 40AA, Freya 40AA, Elomi 40AA, Glamorise 40AA, SHEFIT 40AA, b.tempt'd 40AA, Kindred Bravely 40AA, ENELL 40AA, Fantasie 40AA.

What are the sister sizes for 40O?

40O's sister sizes — same cup volume, different band — are 42N. Try a sister size if the band feels too tight or loose but the cup still fits.

40O Bras

99 bras tracked in 40O · 2 brands · See all O cup

Brands: Elomi, Panache

Your 40O across brands

A 40O isn’t the same in every brand. Here’s how a standard US 40O translates across the brands we track — and how each one runs.

Brand	How it runs	Your 40O →
ThirdLove	cups run generous	40AA
Wacoal	true to size	40AA
Panache	true to size	40AA
Freya	band runs small	40AA
Elomi	cups run generous	40AA
Glamorise	true to size	40AA
SHEFIT	true to size	40AA
b.tempt'd	true to size	40AA
Kindred Bravely	true to size	40AA
ENELL	true to size	40AA
Fantasie	true to size	40AA

Translate across all 30+ brands →

Editorial buying guide

Read the 40O buying guide

Top picks, sister sizes, and how to spot a good 40O fit.

Read →

Sister sizes

42N What are sister sizes?

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Your 40O across brands

Kira Active Balcony Swimsuit - Mulberry

Tango Balcony Bra - Nutmeg

Tango Balcony Bra - Navy

Envy Full Cup Bra - Indigo

Envy Full Cup Bra - Emerald Leopard

Envy Full Cup Bra - Terracotta

Harmony Plunge Bra - Hot Pink

Bliss Full Cup Bra - Lilac

Botanical Balcony Bikini Top - Botanical Floral

Estel Full Cup Bra - Royal Blue

Estel Full Cup Bra - Sage

Josephine Full Cup Bra - Magenta/Latte

Josephine Full Cup Bra - Cobalt/Latte

Natalia Full Cup Bra - Bordeaux Red

Tango Balcony Bra - Chai

Upbeat Wired Sports Bra - Blue

Envy Full Cup Bra - Chai

Envy Full Cup Bra - Chestnut

Envy Full Cup Bra - Teal

Bliss Full Cup Bra - Rose Print

Ella Plunge Bra - Black Sequin

Josephine Full Cup Bra - Forest Green

Renee Balcony Tankini Top - Navy Gingham

Iris Balcony Tankini Top - Green Gingham

Estel Full Cup Bra - Cherry Red

Activate Wired Sports Bra - Black/Chalk

Paloma Balcony Swimsuit - Black Sand Print

Paloma Balcony Swimsuit - Navy Gingham

Paloma Balcony Swimsuit - Green Gingham

Dream Full Cup Bra - Navy

Tango Edit Balcony Bra - White

Anya Riva Spot Balcony Swimsuit - Navy/Vanilla

Anya Riva Balcony Swimsuit - Black

Cate Full Cup Banded Bra: White

Cate Full Cup Banded Bra: Latte

Cate Full Cup Banded Bra: Hazel

Cate Full Cup Banded Bra: Black

Cate Allure Full Cup Banded Bra: Sahara

Tango Balcony Bra - Honey

Tango Balcony Bra - Blush

Tango Balcony Bra - Black

Dream Full Cup Bra - Pistachio

Namrah Bandless Plunge Bra: Pale Blush

Morgan Stretch Banded Bra: Cameo Rose

Lucie Stretch Plunge Bra: Wildcat

Lucie Stretch Plunge Bra: White

Lucie Stretch Plunge Bra: Pale Blush

Lucie Stretch Plunge Bra: Mocha

Lucie Stretch Plunge Bra: Mist

Lucie Stretch Plunge Bra: Black

Morgan Stretch Banded Bra: White

Morgan Stretch Banded Bra: Sahara

Morgan Stretch Banded Bra: Midnight

Morgan Stretch Banded Bra: Haute Red

Morgan Stretch Banded Bra: Black

Morgan Stretch Banded Bra: Toasted Almond

Morgan Stretch Banded Bra: Ebony

Tiernie Stretch Plunge Bra: Sahara

Serene Full Cup Bra - Noir

Molly Nursing Bra: Cameo Rose

Matilda Plunge Bra: White

Matilda Plunge Bra: Sunset

Matilda Plunge Bra: Pearl Blush

Matilda Plunge Bra: Lunar Blue

Matilda Plunge Bra: Cafe Au Lait

Matilda Plunge Bra: Black

Brianna Plunge Bra: Heather

Brianna Plunge Bra: Black

Priya Plunge Bra: Vanilla

Priya Plunge Bra: Black

Molly Nursing Bra: Black

Aerith Plunge Bra: Rose

Zarla Stretch Banded Bra: Rose Bud

Zarla Stretch Banded Bra: Cafe Au Lait

Serene Full Cup Bra - Vintage

Celeste Balcony Bra - Pistachio

Envy Full Cup Bra - Ivory

Envy Full Cup Bra - Navy

Envy Full Cup Bra - Black