Size Guide
40A Bra Size
Everything you need to know about bra size 40A — measurements, sister sizes, international equivalents, and fit advice.
Measurements for 40A
Underbust (Band)
39 to 41 inches (99 to 104 cm)
Full Bust
approximately 42 inches (107 cm)
40A in Other Sizing Systems
US
40A
UK
40A
EU
90A
FR
105A
AU
18A
Sister Sizes for 40A
These sizes have the same cup volume as 40A. Try them if the band feels too tight or too loose.
38B ↔ 40A ↔ 42AA
← Tighter band, bigger cup · Looser band, smaller cup →
Fit Tips for 40A
A-cup bras often benefit from light padding for shape. Bralettes and triangle styles are popular and comfortable.
If your 40A 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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