Bikini Size Chart (Top Cup, Band & Bottom Fit)
A bikini is really two garments: the top is sized like a bra (band plus cup) or by S–XL bust, and the bottom by waist and hip. Because the two halves can be sold and sized separately, matching them is the whole game.
Bikini Size Chart (to-fit body, inches)
| Size | Bust | Underbust (band) | Hip |
|---|---|---|---|
| XS | 31–32 | 26–28 | 34–35 |
| S | 33–34 | 28–30 | 36–37 |
| M | 35–37 | 30–32 | 38–40 |
| L | 38–40 | 32–34 | 41–43 |
| XL | 41–43 | 34–36 | 44–46 |
Notes
Measure the band and the bust for the top. For a cup-sized top, measure snugly under your bust (the band) and around the fullest part (the bust); the difference gives the cup. For an S–XL top, use the bust number. Fixed-triangle tops offer the least support, so a band-and-cup style is worth it for a fuller bust.
Buy the top and bottom to your actual sizes. Many bikinis let you order a different size top and bottom — use that. Forcing a single size onto a body that's, say, a top S and bottom M is the most common reason swimwear gets returned.
Expect swimwear to fit snug dry. Swim fabric relaxes in water, so a bikini should feel snug (not painful) when dry. If it's already loose in the fitting room, it will slip once wet — size down rather than up.
FAQs
How does bikini cup sizing work?
It works like a bra: your band is the snug measurement under the bust, and the cup is the difference between your bust and band measurements. Cup-sized tops give far better support than one-size triangle tops for a fuller bust.
Should I buy the same size top and bottom?
Only if both fit — many brands sell tops and bottoms separately for exactly this reason. Order each half to your actual measurement (bust for the top, hip for the bottom) rather than forcing one size on both.
Do bikinis run small?
Swimwear is cut to fit snugly when dry because it relaxes in water, so it can feel small at first. That's usually intentional — if it fits loosely dry, it will slip when wet.
Need this on your store?
Tailor Size Guide ships pre-built size charts for Shopify.