Bikini Size
Find your bikini size by entering bust, waist, and hip measurements. Free online bikini size calculator with US and international sizing for tops and bottoms.
About This Calculator
Finding the right bikini size can be tricky because swimwear sizing differs from regular clothing. Our free Bikini Size Calculator takes the guesswork out of shopping for swimwear online or in stores. Simply measure your bust, waist, and hips with a soft measuring tape and enter the numbers to get your recommended bikini top size, bottom size, and overall size.
Bikini sizing follows standard womenswear size charts but with some important differences. Swimwear fabrics typically contain more elastane and spandex than regular clothing, meaning the fit can feel different. The calculator uses the most common US/International sizing system, but we recommend checking each brand's specific size chart before making a purchase.
Your bikini top size is determined primarily by your bust measurement, while the bottom size is based on your hip measurement. The waist measurement helps ensure a comfortable overall fit, especially for high-waisted or tie-side styles. If your measurements fall between sizes, we suggest sizing up for a more comfortable fit, particularly for string bikinis and triangle tops where adjustability can compensate for minor sizing differences.
Whether you are shopping for a classic triangle bikini, a supportive underwire style, a sporty high-neck design, or a trendy high-waisted bottom set, having accurate measurements will help you find the perfect fit. Use our calculator every time your body changes, and remember that different brands may size their swimwear differently.
Frequently Asked Questions
How do I measure my bust for a bikini?
Wrap a soft measuring tape around the fullest part of your bust, keeping it parallel to the floor. The tape should be snug against your skin but not digging in. Breathe normally and take the measurement at the end of a natural exhale for the most accurate result.
How does the bikini size calculator determine my size?
The calculator uses standard US/International sizing charts. For the top, your bust measurement determines the band and cup size. For the bottom, your hip measurement determines the size. The overall size is the larger of your top and bottom sizes to ensure the best fit across both pieces.
What if my top and bottom sizes are different?
It is very common to have different top and bottom sizes. Many bikini brands sell tops and bottoms separately so you can mix sizes. The calculator shows each size independently and also suggests an overall size based on the larger measurement. Always try on both pieces or check the brand's specific size chart before purchasing.
Are bikini sizes the same across all brands?
No, bikini sizing varies significantly between brands, countries, and even specific collections. US, UK, EU, and Australian sizing systems all use different measurements for the same size label. Always check the retailer's specific size chart and read customer reviews about fit before ordering, especially when shopping online.
Should I size up or down if I am between sizes?
For bikinis, it is generally recommended to size up rather than down. A slightly looser fit is more comfortable and less likely to cause digging or discomfort. Many bikini fabrics also stretch slightly when wet, so a snug fit in the changing room may become looser at the beach or pool.
How tight should a bikini fit?
A properly fitting bikini top should feel snug but not tight. You should be able to slide two fingers comfortably under the straps and band. The bottom should sit flat against your skin without gaping or rolling at the edges. If the fabric puckers or gaps, the size may be too large. If it digs into your skin or leaves marks, the size is too small.
Can I use this calculator for one-piece swimsuits too?
Yes, the bust, waist, and hip measurements used by this calculator are also the standard measurements used for one-piece swimsuit sizing. Use your overall bikini size as a starting point when shopping for one-piece swimsuits, but always check the brand's size guide as one-piece fits may differ from bikini fits.