Swimsuit size chart: US, UK and EU conversion
Updated: 04.11.2026
In short: UK = US + 4, EU = US + 32. So US 4 = UK 8 = EU 36 (XS), US 6 = UK 10 = EU 38 (S), US 8 = UK 12 = EU 40 (M). Pick bikini bottoms by hip measurement, pick underwire tops by bra size, and pick a one-piece by your largest measurement plus torso length.
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An average chart: always check the brand's own size chart.
Try a swimsuit in this size on your photoWomen's swimsuit size chart
| US | UK | EU | Int. | Bust (in / cm) | Hips (in / cm) |
|---|---|---|---|---|---|
| 2 | 6 | 34 | XXS | 31–32 / 78–82 | 34–35 / 86–90 |
| 4 | 8 | 36 | XS | 32–34 / 82–86 | 35–37 / 90–94 |
| 6 | 10 | 38 | S | 34–35 / 86–90 | 37–38.5 / 94–98 |
| 8 | 12 | 40 | M | 35–37 / 90–94 | 38.5–40 / 98–102 |
| 10 | 14 | 42 | L | 37–38.5 / 94–98 | 40–42 / 102–106 |
| 12 | 16 | 44 | XL | 38.5–40 / 98–102 | 42–43 / 106–110 |
| 14 | 18 | 46 | XXL | 40–42 / 102–106 | 43–45 / 110–114 |
| 16 | 20 | 48 | 3XL | 42–43 / 106–110 | 45–46.5 / 114–118 |
This is an average chart. Brands differ, so always check the size chart on the product page.
How to measure
- Bust: around the fullest part, with the tape level.
- Underbust: snug, right under the bust. You need this for underwire tops; see how to measure bra size.
- Hips: around the fullest part of your hips and seat.
- Torso (one-pieces): from the top of your shoulder, down through the crotch and back up to the same shoulder. A long torso needs "long torso" styles.
Between two sizes?
- One-piece: go by hips and torso length; a one-piece that's too short digs in everywhere.
- Bikini: buy the top and bottom separately when the store allows it.
- Fabric: power-mesh and shaping fabrics run small; thin jersey stretches.
- Reviews: "runs small" means size up.
Size is half the job
Swimwear is often final sale, so check the style too. Try the swimsuit on your own photo and see how the cut and color look on you before you order.
FAQ
What size is EU 38 in US swimwear?
EU 38 = US 6 = UK 10 = S.
What is a size 12 swimsuit in UK?
US 12 = UK 16 = EU 44 (XL). A UK 12 is a US 8.
Should I size up in swimwear?
Only if you're between sizes or the reviews say it runs small. Swimwear should be snug when dry.