Size Guide
40B Bra Size
Everything you need to know about bra size 40B — measurements, sister sizes, international equivalents, and fit advice.
Measurements for 40B
Underbust (Band)
39 to 41 inches (99 to 104 cm)
Full Bust
approximately 43 inches (109 cm)
40B in Other Sizing Systems
US
40B
UK
40B
EU
90B
FR
105B
AU
18B
Sister Sizes for 40B
These sizes have the same cup volume as 40B. Try them if the band feels too tight or too loose.
38C ↔ 40B ↔ 42A
← Tighter band, bigger cup · Looser band, smaller cup →
Fit Tips for 40B
B cups are among the most widely available sizes. If gapping occurs, try a demi-cup or push-up style.
If your 40B bra is gapping at the top of the cup, the cup may be too large or the wrong shape — try a demi-cup or balconette. If the center gore doesn't sit flat, go up one cup size.
Not sure about your size? Measure yourself and double-check.
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