BraSizeConversion

34C Bra Size, Fully Explained

7 sizing systems25+ country calculatorsBands 28-60, cups AA-PZero data stored

34C sits in the heart of the bestselling range, the sizes every brand cuts first and fits its patterns around. That works in your favor: the full breadth of styles exists in 34C, so shape-matching rather than size-hunting is where your effort pays.

34C in every sizing system

USUKEUFRAUJPKR
34C34C75C90C12CD75D75

Sister sizes of 34C

30DD32D34C36B38A

Each sister holds roughly the volume of 34C on a different band. Band riding up in a 34C? Try 32D. Band digging painfully? The other direction.

How 34C compares, visually

34B34C34D

Circle areas scale with estimated cup volume: 34C415 cc per cup, roughly 0.4 kg of tissue per side at typical density. Model documented on the weight page.

Is 34C big?

Is 34C big? It is close to the middle of the real-world distribution: commonly reported averages in the US and UK land within a letter of this size, though survey methods vary widely. On a 34 band this difference is proportionate rather than dramatic, whatever cup-letter folklore suggests.

Shopping notes for 34C

Confirm the size first: two minutes with the calculator beats inheriting a label. Then let the brand decoder translate 34C into each brand's cut, since the same tag runs shallow at mall brands and deep at UK houses. If 34C passes the band checks but the cup misbehaves, that is usually shape, not size.

Frequently asked questions

What is 34C in UK and European sizing?
34C (US) converts to UK 34C, EU 75C, FR 90C, AU 12C and JP/KR D75. Cup letters diverge after D, which is why the letters differ between systems.
What are the sister sizes of 34C?
30DD, 32D, 36B, 38A. Each holds approximately the same cup volume as 34C on a different band: band down pairs with letter up, and vice versa.
Is 34C big?
On a 34 band this difference is proportionate rather than dramatic, whatever cup-letter folklore suggests..
How much do 34C breasts weigh?
Roughly 0.4 kg (0.8 lb) per breast as an estimate from cup volume at typical tissue density. Real weight varies with tissue composition; see our breast weight page for the method.
Nearby sizes

Last updated August 2026.