What is 30B Bra Size? 30B Measurements in Inches & cm, Sister Sizes and Fit

A 30B bra size means a 30 band (your underbust measures about 25 to 26 inches) and a B cup (your bust measures about 32 inches, 2 inches more than the band). In centimetres that is an underbust of 64 to 66 cm and a bust of about 81 cm. 30B is the most common 30 size, usually worn by teenagers and petite women; many who wear 30B could also wear 32A. Lovable India sells 30B in every style from non-padded cotton to t-shirt, padded and sports bras: see all 30B bras.

30B bra size measurements

Measurement	Inches	Centimetres
Underbust (band 30)	25–26	64–66
Bust (cup B)	32	81
Bust minus band	2	5

The band number is not your bust; it is your underbust plus 4 (even) or 5 (odd) inches, which is how Indian and international brands size bras. The cup letter is the difference between bust and band: A is 1 inch, B is 2, C is 3, D is 4, E is 5.

How to check if you are a 30B

Wrap a soft tape snugly under your bust and note the inches. 25 or 26 inches points to band 30.
Wrap the tape loosely around the fullest part of your bust. About 32 inches with a 30 band points to a B cup.
Try the bra: the band should sit level across your back on the loosest hook, the centre panel should touch your breastbone, and the cup should be full with no gap and no spill.

If the numbers do not match this exactly, use the full bra size chart or the bra size calculator.

30B sister sizes

Sister sizes hold the same cup volume on a different band. If a 30B band feels tight, try 32A; if it rides up and feels loose, the sister size is 28C, but few Indian brands stock a 28 band, so most women tighten to the inner hook instead. The cup letter changes but the cup itself stays the same size.

If 30B…	Try	Why
band is tight, cup fits	32A	looser band, same cup volume
cup spills over	30C	same band, one cup larger
cup gaps or wrinkles	30A	same band, one cup smaller

30B compared with nearby sizes

30B vs 30A: same band; 30B has a cup one inch larger (bust 32 vs 31 inches).
30B vs 30C: same band; 30C has a cup one inch larger (bust 33 inches).
30B vs 32B: same cup letter, but 32B has a 2-inch longer band and a slightly larger cup, because cup volume grows with band size. 32A is the true equivalent of 30B, not 32B.

Best bra styles for 30B

B cups suit almost every style. Lightly padded and push-up bras add shape under fitted tops; t-shirt and seamless bras disappear under thin fabrics; non-padded cotton bras are the coolest daily option; non-wired works fine because the cup is light. Browse by style: t-shirt bras, padded bras, non-padded bras, seamless bras, sports bras and full coverage bras, then filter to 30B.

30B bra FAQs

Is 30B a small, medium or large bra size?

30B is a small size: the smallest standard band with a modest cup. The cup letter alone does not tell you the volume: a B cup on a 30 band is a different size from a B cup on a 34 band.

What is 30B bra size in cm?

Underbust 64 to 66 cm and bust about 81 cm. European sizing calls this 65B.

What is the difference between 30B and 32B?

The band. 32B is for an underbust of 27 to 28 inches, 30B for 25 to 26 inches. Because cup volume scales with the band, the 32B cup is also a little larger than the 30B cup.

My 30B band rides up at the back. What should I do?

The band is too loose. Tighten to the inner hook or go down a band size and up a cup to keep the same cup volume.

Which 30B bra is best for daily use?

A non-padded or lightly padded, non-wired, full-coverage cotton bra. See 30B bras on Lovable India from ₹179.

Does 30B change after weight gain or loss?

Usually by one band size for every 5 to 7 kg, and sometimes a cup. Re-measure every six months and after any change in weight, pregnancy or exercise.

More bra size guides

Bra Size Chart | Bra Size Calculator | What A, B, C, D Cup Sizes Mean

By band: 30 Bra Size | 32 Bra Size | 34 Bra Size | 36 Bra Size | 38 Bra Size

By size: 32B | 32C | 32D | 34B | 34C | 34D | 36B | 36C | 36D | 38B | 38C | 38D

By cup: A Cup | B Cup | C Cup | D Cup

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