Reviewed
40J (UK 40GG) bra size
A 40J has a 40-inch band and a J cup, about 10 inches between band and bust. In the UK it is 40GG, in Australia 18GG and in Europe 90J.
- US
- 40J
- UK
- 40GG
- AU
- 18GG
- EU
- 90J
- FR
- 105J
Also fits (sister sizes): 38K firmer band · 42I looser band · all same-volume sizes ↓
40J measurements
- Snug underbust
- 40–41 in · 102–104 cm
- Bust, fullest part
- about 50 in · 126–128 cm
- Cup difference
- 10 in (J 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.
40J sister sizes
Same cup volume, different band. If a 40J 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 40J doesn't fit
- Band rides up at the back
- Try 38K
- Band digs in, cups fit
- Try 42I
- Spilling over the cups
- Try 40K
- Cups gape or wrinkle
- Try 40I
Not sure what's wrong? Run through the 4-point fit check.
40J questions
What is the sister size of 40J?
38K (one band down, one cup up) and 42I (one band up, one cup down). Sister sizes hold the same cup volume on a different band.
What is 40J in UK, Australian and European sizes?
UK 40GG, Australia 18GG, Europe 90J and France 105J. US and UK cup letters match up to DD and then split.
What measurements are a 40J?
A snug underbust of about 40–41 in (102–104 cm) and a bust of about 50 in (126–128 cm). Measure with the tape level and use the calculator for an exact result.
Is 40J a big size?
40J has a very full cup volume for a 40 band. Cup letters only mean something next to the band: a 40J holds the same as 30O or 32N.