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Buying guide · US 30B

The Best Bras for 30B

A 30B is stocked almost everywhere: 35 of our 49 charted brands cut it, which moves the question from availability to judgment. Start with the picks below, then use the full computed table to compare how every brand labels and positions your size, and choose by construction for a small ribcage with a shallower cup.

One size, every label

30B in every system

US 30BUK 30BEU / DE 65BFR / ES 80BAU / NZ 8BIT 1ªBJP C65

Cup letters diverge above D, so the letter changes even though the bra does not. Convert by position, and match the printed tag in the table below.

Start here

Strong first tries at 30B

These are chosen by rule, not payment: your size sits inside each chart, away from its edges. The complete computed list follows.

Computed, not sponsored

The complete list: who makes 30B

BrandSystemTheir label for itRange positionInteractive chart
M&SUK30Bwell in rangechart →
AerieUS30Bat chart edgechart →
AnitaEU65Bat chart edgechart →
AubadeFR80Bat chart edgechart →
BendonAU8Bat chart edgechart →
BerleiAU8Bat chart edgechart →
Boux AvenueUK30Bat chart edgechart →
Bras N ThingsAU8Bat chart edgechart →
Calvin KleinUS30Bat chart edgechart →
ChantelleFR80Bat chart edgechart →
CuupUS30Bat chart edgechart →
EtamFR80Bat chart edgechart →
FreyaUK30Bat chart edgechart →
GossardUK30Bat chart edgechart →
Harper WildeUS30Bat chart edgechart →
HunkemöllerEU65Bat chart edgechart →
IntimissimiIT1ªBat chart edgechart →
KnixUS30Bat chart edgechart →
La PerlaIT1ªBat chart edgechart →
Le MystèreUS30Bat chart edgechart →
Marie JoEU65Bat chart edgechart →
NatoriUS30Bat chart edgechart →
Peach JohnEU65Bat chart edgechart →
PepperUS30Bat chart edgechart →
Pour MoiUK30Bat chart edgechart →
Savage X FentyUS30Bat chart edgechart →
Shock AbsorberUK30Bat chart edgechart →
Simone PérèleFR80Bat chart edgechart →
ThirdLoveUS30Bat chart edgechart →
TriumphEU65Bat chart edgechart →
Triumph JapanEU65Bat chart edgechart →
Victoria’s SecretUS30Bat chart edgechart →
WacoalUS30Bat chart edgechart →
Wacoal JapanEU65Bat chart edgechart →
YamamayIT1ªBat chart edgechart →

Of the 35: 1 carry 30B well inside their chart, 34 at its edge. Well in range means the size sits inside the brand's chart, cut from a block graded around it. At chart edge means it is the first or last size they make, which is real but drafted at the limit of their grading. Your measured size guide: the universal 30B page.

Check first

Is 30B actually your size?

Snug underbust, relaxed bust. Tap the unit to switch inches and centimeters.

Same published math as the calculator: snug measure, no added inches.

Choosing well

How to choose at 30B

At 30B the challenge is rarely support, it is proportion. Standard wires and cup heights are drafted for larger frames, so on a small ribcage the wire can sit wide of the breast root and the cup top can gape even when the volume is right.

Prioritize narrow wires, shorter cup heights and stretch or partially stretch top edges. Demi and balconette cuts follow a shallower profile far better than tall full-coverage cups, and unlined stretch styles remove the rigid-cup fit problem entirely.

Band feel matters more at small sizes than reviews suggest: with less breast weight, a band that is merely adequate will not announce itself, so check the two-finger test rather than comfort alone.

Watch for: Watch for cup gaping at the top edge: it usually means the cup is too tall for your profile, not that the size is wrong. The cup gaping guide covers the diagnosis.

Styles that earn it

Constructions that work for a small ribcage with a shallower cup

Each guide explains the construction, who it flatters and its honest trade-offs.

Same volume, different band

Sister sizes for 30B

A sister size keeps identical cup volume on a different band. If the 30B band rides up or digs in while the cup fits, the sister is the fix.

Answered

30B bras, answered

Which brands make a 30B bra?

Of the 49 brands whose published size charts we track, 35 cut a 30B. The strongest first tries: M&S. The full table on this page lists every one in the brand's own notation, converted by chart position.

What is 30B in other sizing systems?

US: 30B. UK: 30B. EU / DE: 65B. FR / ES: 80B. AU / NZ: 8B. IT: 1ªB. JP: C65. Letters diverge above D, so always convert by position, not by letter.

What styles work best for 30B?

For a small ribcage with a shallower cup: Demi, Balconette, Unlined, Bralette, T-shirt. Watch for cup gaping at the top edge: it usually means the cup is too tall for your profile, not that the size is wrong. The cup gaping guide covers the diagnosis.

Ready to shop

Multi-brand retailers with deep size ranges

Shop links may earn a commission; your price does not change, and commissions never touch the computed tables above. How this site makes money. HauteFlair shares ownership with this site, disclosed here.

Shop itAt HauteFlair, our sister retailer

HauteFlair labels cups in UK letters, so these links already convert your size by position (a US DDD lands on a UK E, a US G on a UK F). HauteFlair is owned by the same company as Brasize.ai; that relationship never changes the sizing math, charts, or fit advice on this page. How this site makes money.

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