Swimwear Size Calculator
Three measurements (bust, waist, hip) and you have your US swimwear size. Works for activewear too. Always cross-check the size guide on the product page: cuts vary by style.
How to take your measurements
- 1. Bust. Wrap a soft tape around the fullest part of your bust, keeping it level front to back.
- 2. Waist. Measure your natural waist, the narrowest point above the belly button. Don't suck in.
- 3. Hip. Stand with feet together and measure around the fullest part of your hips and seat.
- 4. Enter all three above. If they land in different sizes, we recommend the larger for comfort in stretch fabrics.
US swimwear size chart
| Size | US | Bust (in) | Waist (in) | Hip (in) |
|---|---|---|---|---|
| XS | 0 to 2 | 31 to 33 | 23.5 to 25.5 | 34 to 36 |
| S | 4 to 6 | 33 to 35 | 25.5 to 27.5 | 36 to 38 |
| M | 8 to 10 | 35 to 37.5 | 27.5 to 30 | 38 to 40.5 |
| L | 12 to 14 | 37.5 to 40.5 | 30 to 33 | 40.5 to 43.5 |
| XL | 16 to 18 | 40.5 to 43.5 | 33 to 36.5 | 43.5 to 46.5 |
| 1X to 3X | 18W+ | 43.5 to 52 | 36.5 to 46 | 46.5 to 55 |
Guideline only. Each product page carries the exact chart for that garment. When the two differ, trust the product page.
Swimwear fit FAQs
How do I measure myself for a swimsuit?
You need three measurements with a soft tape: bust (around the fullest part, tape level), waist (the natural waist, the narrowest point above your belly button), and hip (around the fullest part of your hips and seat). Measure over underwear, not over clothes, and keep the tape snug but not tight.
What if my top and bottom are different sizes?
Very common. For bikinis, simply mix sizes. Many of our bikini sets are sold as sets but sized generously enough to fit a one-size difference. For one-pieces, size to the LARGER measurement; a slightly relaxed fit beats a suit that digs in.
Should I size up or down in swimwear?
If you sit between sizes, size up. Swim fabric is stretchy and a suit that is slightly relaxed stays comfortable in the water, while one that is too small digs and distorts.
Is activewear sizing the same as swimwear?
Broadly yes. Both use standard US sizing with 4-way-stretch fabrics, so the size this calculator gives you is a good starting point for leggings and sports tops too. Compression styles run tighter by design.
Why does the product page size chart differ from this one?
Cuts vary by style and brand. This calculator gives you the standard US baseline, while each Fashorio product page carries the exact chart for that garment. When they differ, trust the product page.
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Swim and activewear share standard US sizing, so the size above is your starting point. Every product page carries its own size guide, so you can buy with confidence.