Reviewed
38B vs 40B
40B is bigger than 38B. The cup letter is the same, but cup volume grows with the band, so 40B's cups hold more as well as having the longer band.
Side by side
| 38B | 40B | |
|---|---|---|
| Relationship | Same cup letter, different band | |
| UK | 38B | 40B |
| AU | 16B | 18B |
| EU | 85B | 90B |
| FR | 100B | 105B |
| Underbust | 38–39 in | 40–41 in |
| Bust | ≈ 40 in | ≈ 42 in |
| Cup volume | 40B holds more | |
On the size chart
38B is marked in ink and 40B is outlined. The yellow diagonal through 38B shows every size with the same cup volume.
A
B
C
D
DD
DDD
G
H
28
30
32
34
36
38
40
42
44
Read each size
Questions
Is 38B or 40B bigger?
40B is bigger than 38B. The cup letter is the same, but cup volume grows with the band, so 40B's cups hold more as well as having the longer band.
Can I wear 40B if I'm a 38B?
Only if the fit check says so. Changing the band also changes the cup volume, so try both where returns are easy.
What are 38B and 40B in UK sizes?
38B is UK 38B and 40B is UK 40B. In Europe they are 85B and 90B.