Swimsuit size from bra size, explained
Updated: 05.11.2026
In short: swimwear is sized two ways. Bra-sized tops (like 34C) follow your bra size exactly, so buy the top in your usual bra size and the bottom in your dress size. Dress-sized swimsuits (6, 8, 10 or S, M, L) follow your bust and hips; a "size 34 equivalent" usually means the EU 34, which is about US 2 / UK 6 / XS. When your top and bottom are different sizes, choose a bikini sold as separates, and for a one-piece go by the larger measurement.
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Two ways swimwear is sized
| Sizing | Looks like | Choose it by |
|---|---|---|
| Bra-sized | 32B, 34C, 36DD | Your bra band and cup |
| Dress-sized | 4, 6, 8 or XS, S, M | Bust and hips, like clothing |
| Mixed (separates) | Top 34D, bottom M | Top by bra size, bottom by hips |
Bra-sized swimwear gives the best support for a bigger bust. If you don't know your bra size, see how to measure bra size.
"Size 32, 34, 36 equivalent": the conversion chart
| EU | UK | US | Letter | Bust, in (cm) | Hips, in (cm) |
|---|---|---|---|---|---|
| 32 | 4 | 0 | XXS | 30–31 (77–80) | 33–34 (85–88) |
| 34 | 6 | 2 | XS | 32–33 (81–84) | 35–36 (89–92) |
| 36 | 8 | 4 | S | 34–35 (85–88) | 37–38 (93–96) |
| 38 | 10 | 6 | M | 35–36 (89–92) | 38–39 (97–100) |
| 40 | 12 | 8 | M/L | 37–38 (93–96) | 40–41 (101–104) |
| 42 | 14 | 10 | L | 38–40 (97–101) | 41–43 (105–109) |
| 44 | 16 | 12 | XL | 40–42 (102–106) | 43–44 (110–113) |
This is an average chart. Every brand has its own, so always check the size chart on the product page. Our swimsuit size chart has more detail.
From bra size to a dress-sized top
There is no exact match, but this rough guide helps when a top only comes in S/M/L:
| Bra size | Usual swim top |
|---|---|
| 32A–32B | XS |
| 34A–34B, 32C | S |
| 34C, 36B | M |
| 36C, 34D | M or L (or a bra-sized top) |
| 36D and up | Bra-sized top for support |
From a D cup up, S/M/L tops often fit the band but not the cup. Look for bra-sized or "DD+" swimwear.
Tips before you order
- One-piece: go by your larger measurement and check the torso length; long torsos need "long torso" styles.
- Bikini: buy the top and bottom separately if they're different sizes.
- Reviews: "runs small" means size up; check photos from buyers with a similar shape.
- Final sale: swimwear is often not returnable, so check the fit and look first.
See the fit before you buy
The size tells you whether it will close; it doesn't tell you how the cut looks on you. Try the swimsuit on your own photo: paste a link from Amazon, SHEIN or any store and see it on you in about 30 seconds.
FAQ
What does "swimsuit size 34 equivalent" mean?
Usually the European size 34, which is about a US 2, UK 6 or XS. Check the brand's chart, because some stores use 34 to mean a 34-inch bust or a 34 bra band.
Is my swimsuit top size the same as my bra size?
For bra-sized and underwire tops, yes. For triangle, bandeau and S/M/L tops, use the brand's chart and the rough guide above.
What size swimsuit is a 36C?
In bra-sized swimwear, a 36C top. In S/M/L, usually an M or L, depending on the brand.
Should I size up or down in swimwear?
Swimwear is tighter than clothing and stretches in water, so take your measured size. Size up only if reviews say the style runs small.