A D cup means your bust measures about 4 inches more than your band. On a 36 band that’s roughly 40 inches at the fullest point. D isn’t automatically large: a 30D holds about the same volume as a 32C or a 34B. US, UK, EU and Australian sizing all use the letter D.
| Band 36 | Underbust over 34 and up to 36 inches (86–91 cm). We round your underbust up to the next even number. |
|---|---|
| Cup D | Bust about 4 inches bigger than the band: roughly 39½ to 40½ inches (100–103 cm) around the fullest part. |
| Sister sizes | 34DD (tighter band) and 38C (looser band). Full diagonal: 28H (UK 28FF), 30G (UK 30F), 32DDD (UK 32E), 34DD, 36D, 38C, 40B, 42A, 44AA. |
| Same size abroad | UK 36D · EU 80D · French 95D · Australia / NZ 14D |
Brands measure differently, and some US brands add inches to the band. Use these numbers as a starting point, then check the fit. Calculate your own size · See every sister size · Convert another size
D cup sizes across bands
| Size | Underbust (in) | Bust (approx. in) | Sister sizes |
|---|---|---|---|
| 30D | 28–30 | 34 | 28DD, 32C |
| 32D | 30–32 | 36 | 30DD, 34C |
| 34D | 32–34 | 38 | 32DD, 36C |
| 36D | 34–36 | 40 | 34DD, 38C |
| 38D | 36–38 | 42 | 36DD, 40C |
| 40D | 38–40 | 44 | 38DD, 42C |
| 42D | 40–42 | 46 | 40DD, 44C |
Our guides to 32D, 34D, 36D and 38D go deeper on each one.
Is a D cup big?
Volume depends on the band, so a D cup can be modest or full. Brastop’s sister size guide explains the diagonal: 30D, 32C and 34B all share the same cup volume. The letter alone tells you very little; the band and cup together do.
The best bra styles for D cups
- Full cup: maximum coverage and support for everyday wear.
- Balconette: lifts from below; good if you’re fuller at the bottom.
- T-shirt bra with side support: smooth under fitted tops.
- Plunge: for V necklines and close-set breasts.
- Minimizer: if you want a smaller-looking profile. See our minimizer bra guide.
How to tell if you’re really a D
Measure snugly around your ribcage and round up to the next even number, then measure loosely around the fullest part of your bust. 4 inches is a D. If you’ve been wearing a bigger band with a smaller cup (say 38B), you may actually be closer to a 34D or 36C once the band is firm. The bra size calculator shows your size in any system.
Shop D cup bras by size
Affiliate links-
32D bras
Smaller band; check the brand stocks it before you choose a style.
Search Amazon for 32d bras (opens in a new tab, affiliate link) -
34D bras
Widely stocked across brands and styles.
Search Amazon for 34d bras (opens in a new tab, affiliate link) -
36D bras
Look for side support and wider straps.
Search Amazon for 36d bras (opens in a new tab, affiliate link) -
D cup sports bras
Encapsulation styles control bounce better than compression.
Search Amazon for d cup sports bras (opens in a new tab, affiliate link)
Results are Amazon’s, not our picks. Check the size range, the return policy and the features above before you buy.
D vs DD vs DDD
On the same band, each step adds about an inch: D is 4 inches, DD is 5 and DDD is 6. Our guide to D vs DD explains the difference in detail, and the DD cup page covers the next size up.
