Bikini Size Calculator
Pick your style, choose a color, and see your size on a 3D-style model preview — plus your top and bottom size from three quick measurements.
How bikini sizing works
This calculator keeps it simple with the XS–XL scale most swim brands use. Your top size comes from your bust measurement, and your bottom size comes from the larger of your high-hip and low-hip measurements — so each half of the set fits the body it's made for. Measurements in centimeters are converted to inches automatically.
| Top size | Bust (inches) |
|---|---|
| XS | 32 and under |
| S | 33–34 |
| M | 35–36 |
| L | 37–39 |
| XL | 40 and over |
| Bottom size | Hips (inches) |
|---|---|
| XS | 34 and under |
| S | 35–36 |
| M | 37–38 |
| L | 39–41 |
| XL | 42 and over |
3D-style try-on preview
Choose one of five bikini styles and a color, then switch between front, side and back views to see your pick on a stylized fit model. Your calculated top and bottom size appears as a badge on the preview, and changing the style or color updates the model instantly — no need to recalculate. The preview is a stylized illustration for comparing styles and colors, not an exact fitting, so always check the brand's own size chart before buying.
Measuring & fit tips
- Measure snug, not tight. The tape should sit flat against your skin without digging in or slipping — breathe normally and keep it level all the way round.
- Skip the padded bra. Measure over bare skin or an unpadded bra for the truest bust reading.
- Use sister sizes for the top. If the band feels tight but the cups fit, go up a band and down a cup (34C → 36B). If it rides up, go down a band and up a cup (34C → 32D).
- Mix and match. It's completely normal to need a different top and bottom size — separates exist for exactly this reason.
- Check the brand's chart. Swimwear sizing varies more than everyday clothing, so compare your measurements to each brand's own chart before ordering.
Frequently asked questions
How is a bikini top size different from a regular bra size?
Many bikini tops do use the same band-and-cup system as bras, but most swim brands also sell simple XS–XL sizing — which is what this calculator gives you. If your top lists a band and cup, use our bra size calculator to convert; the bust measurement is the same either way.
Should I size up in bikini bottoms?
If your hips fall between two sizes, sizing up usually gives a more comfortable fit — swim fabric stretches but shouldn't dig in. If you prefer minimal coverage or the style runs large, stay with your measured size.
Why do I need different top and bottom sizes?
Very few bodies match one size on top and bottom, so it's completely normal for your top and bottom sizes to differ. Buying separates — or choosing a size from both charts — gives a far better fit than a single one-size set.
Do bikini sizes differ between brands?
Yes — swimwear sizing varies more than everyday clothing. Use your body measurements against each brand's own size chart rather than assuming your usual high-street size.
How does the 3D model preview work?
Pick a bikini style and a color, then switch between front, side and back views to see your selection on a stylized fit model. It's an illustration for comparing styles and colors — not an exact fitting — so try swimwear on in store before buying.