Reviewed
30B bra size
A 30B has a 30-inch band and a B cup, about 2 inches between band and bust. In the UK it is 30B, in Australia 8B and in Europe 65B.
- US
- 30B
- UK
- 30B
- AU
- 8B
- EU
- 65B
- FR
- 80B
Also fits (sister sizes): 28C firmer band · 32A looser band · all same-volume sizes ↓
30B measurements
- Snug underbust
- 30–31 in · 76–79 cm
- Bust, fullest part
- about 32 in · 80–83 cm
- Cup difference
- 2 in (B cup)
These are starting points from the band-and-cup method. Brands differ by about a size, so a two-minute measurement beats any chart.
30B sister sizes
Same cup volume, different band. If a 30B band feels too loose, go down a band and up a cup; if it feels tight, go up a band and down a cup.
If a 30B doesn't fit
- Band rides up at the back
- Try 28C
- Band digs in, cups fit
- Try 32A
- Spilling over the cups
- Try 30C
- Cups gape or wrinkle
- Try 30A
Not sure what's wrong? Run through the 4-point fit check.
Compare 30B
Sizes next to 30B
30B questions
What is the sister size of 30B?
28C (one band down, one cup up) and 32A (one band up, one cup down). Sister sizes hold the same cup volume on a different band.
What is 30B in UK, Australian and European sizes?
UK 30B, Australia 8B, Europe 65B and France 80B. US and UK cup letters match up to DD and then split.
What measurements are a 30B?
A snug underbust of about 30–31 in (76–79 cm) and a bust of about 32 in (80–83 cm). Measure with the tape level and use the calculator for an exact result.
Is 30B a big size?
30B has a mid-range cup volume for a 30 band. Cup letters only mean something next to the band: a 30B holds the same as 28C or 32A.