Reviewed
40DD bra size
A 40DD has a 40-inch band and a DD cup, about 5 inches between band and bust. In the UK it is 40DD, in Australia 18DD and in Europe 90E.
- US
- 40DD
- UK
- 40DD
- AU
- 18DD
- EU
- 90E
- FR
- 105E
Also fits (sister sizes): 38DDD firmer band · 42D looser band · all same-volume sizes ↓
40DD measurements
- Snug underbust
- 40–41 in · 102–104 cm
- Bust, fullest part
- about 45 in · 113–116 cm
- Cup difference
- 5 in (DD 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.
40DD sister sizes
Same cup volume, different band. If a 40DD 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 40DD doesn't fit
- Band rides up at the back
- Try 38DDD
- Band digs in, cups fit
- Try 42D
- Spilling over the cups
- Try 40DDD
- Cups gape or wrinkle
- Try 40D
Not sure what's wrong? Run through the 4-point fit check.
Compare 40DD
Sizes next to 40DD
40DD questions
What is the sister size of 40DD?
38DDD (one band down, one cup up) and 42D (one band up, one cup down). Sister sizes hold the same cup volume on a different band.
What is 40DD in UK, Australian and European sizes?
UK 40DD, Australia 18DD, Europe 90E and France 105E. US and UK cup letters match up to DD and then split.
What measurements are a 40DD?
A snug underbust of about 40–41 in (102–104 cm) and a bust of about 45 in (113–116 cm). Measure with the tape level and use the calculator for an exact result.
Is 40DD a big size?
40DD has a very full cup volume for a 40 band. Cup letters only mean something next to the band: a 40DD holds the same as 28K or 30J.