Is a 30K the same in every brand?

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

What are the sister sizes for 30K?

30K's sister sizes — same cup volume, different band — are 28L and 32J. Try a sister size if the band feels too tight or loose but the cup still fits.

30K Bras

What is a 30K in other brands?

343 bras tracked in 30K · 4 brands · See all K cup

Brands: Bravissimo, Fantasie, Freya, Panache

Your 30K across brands

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

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

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

Editorial buying guide

Read the 30K buying guide

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

Read →

Sister sizes

28L 32J What are sister sizes?

Sort

Your 30K across brands

Lacey Bra - Beige

Lacey Bra - Black

Lacey Bra - White

Power Wired Sports Bra - White

Endurance Wired Sports Bra - Black

Power Wired Sports Bra - Latte

Endurance Wired Sports Bra - Dusty Rose

Endurance Wired Sports Bra - Berry/Chalk

Endurance Wired Sports Bra - Sienna Rose

Bette Balcony Bikini Top - Teal Blue

Magdalena Spacer Molded Bra: Vintage Green

Magdalena Spacer Molded Bra: Noir

Magdalena Spacer Molded Bra: Natural Beige

The Shoulder Ease Bra - Steel Blue

Niya Smoothing Bra - Smokey Green

Millie Luxe Bra - Black

Millie Luxe Bra - White

Niya Smoothing Bra - Beige

Niya Smoothing Bra - White

Millie Luxe Bra - Teal

Niya Smoothing Bra - Black

Una Bra - Forest Green

Millie Luxe Bra - Burgundy

Niya Smoothing Bra - Mocha

Millie Luxe Bra - Amber

Una Bra - Black

Millie Luxe Bra - Forest Green

Endurance Wired Sports Bra - Black/Latte

Lara Plunge Swimsuit - Aurora Red

Millie Nursing Bra - Black

Apollo Sports Bra - Black

Inspire High Impact Sports Crop - Black

Iris Balcony Tankini Top - Black Gingham

Isabella Balcony Swimsuit - Polka Dot Print

Paloma Balcony Swimsuit - Red Gingham

Paloma Balcony Swimsuit - Black Gingham

Rita Plunge Swimsuit - Black

Monica Balcony Swimsuit - Liliflora Print

Monica Balcony Swimsuit - Teal Blue

Lara Plunge Swimsuit - Aurora Black/White

Rita Plunge Swimsuit - Cobalt

Rita Plunge Swimsuit - Red

Gigi Balcony Swimsuit - Sparkle Teal