Reviewed
40A bra size
A 40A has a 40-inch band and a A cup, about 1 inches between band and bust. In the UK it is 40A, in Australia 18A and in Europe 90A.
- US
- 40A
- UK
- 40A
- AU
- 18A
- EU
- 90A
- FR
- 105A
Also fits (sister sizes): 38B firmer band · 42AA looser band · all same-volume sizes ↓
40A measurements
- Snug underbust
- 40–41 in · 102–104 cm
- Bust, fullest part
- about 41 in · 103–105 cm
- Cup difference
- 1 in (A 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.
40A sister sizes
Same cup volume, different band. If a 40A 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 40A doesn't fit
Not sure what's wrong? Run through the 4-point fit check.
Compare 40A
Sizes next to 40A
40A questions
What is the sister size of 40A?
38B (one band down, one cup up) and 42AA (one band up, one cup down). Sister sizes hold the same cup volume on a different band.
What is 40A in UK, Australian and European sizes?
UK 40A, Australia 18A, Europe 90A and France 105A. US and UK cup letters match up to DD and then split.
What measurements are a 40A?
A snug underbust of about 40–41 in (102–104 cm) and a bust of about 41 in (103–105 cm). Measure with the tape level and use the calculator for an exact result.
Is 40A a big size?
40A has a fuller cup volume for a 40 band. Cup letters only mean something next to the band: a 40A holds the same as 28G or 30DDD.