Bikini Size Calculator
Our clothing & sewing calculator computes bikini size instantly. Get useful results with practical tips and recommendations.
Formula
Top Size = f(bust) | Bottom Size = f(hips) | Cup = bust - underbust
Bikini top sizes are determined by bust circumference measurements, with cup size calculated as the difference between bust and underbust measurements. Bottom sizes are based on hip circumference. Sizing charts vary by brand and region.
Worked Examples
Example 1: Standard Fit Assessment
Problem: A woman measures bust 36 inches, waist 28 inches, hips 38 inches, and underbust 32 inches. What bikini size should she choose?
Solution: Bust 36\" → Top: M (US 8-10)\nCup: 36 - 32 = 4\" difference → C cup\nHips 38\" → Bottom: M (US 8-10)\nWaist-Hip Ratio: 28/38 = 0.74 → Hourglass shape
Result: Top: M (US 8-10, EU 38) | Bottom: M | Cup: C | Hourglass
Example 2: Mixed Size Scenario
Problem: A woman measures bust 34 inches, waist 30 inches, hips 42 inches. Determine top and bottom sizes.
Solution: Bust 34\" → Top: S (US 4-6, EU 36)\nHips 42\" → Bottom: XL (US 16-18, EU 42)\nWaist-Hip Ratio: 30/42 = 0.71 → Pear shape\nRecommendation: Mix-and-match sizes needed.
Result: Top: S (US 4-6) | Bottom: XL (US 16-18) | Pear shape
Frequently Asked Questions
How do I accurately measure myself for a bikini?
To measure yourself accurately for a bikini, you need a soft measuring tape and should wear only lightweight undergarments or nothing at all. For the bust, wrap the tape around the fullest part of your chest, keeping it level and snug but not tight. The underbust measurement goes directly below the breast tissue around the ribcage. Measure your waist at the narrowest point, typically just above the navel. For hips, measure around the widest part of your buttocks and hips. Stand naturally without sucking in your stomach. Take measurements twice to confirm accuracy. Record everything in the same unit (inches or centimeters) and avoid measuring over bulky clothing.
What is the difference between bikini top and bottom sizes?
Bikini tops and bottoms are often sized independently because most women have different proportions between their upper and lower body. The top size is determined primarily by the bust and underbust measurements, while the bottom size depends on hip and waist measurements. Many brands allow you to purchase mix-and-match sizes, meaning you might wear a medium top and a large bottom, or vice versa. Some brands size tops like bras using band and cup sizes (e.g., 34C), while others use standard S/M/L sizing. Bottoms typically follow standard sizing based on hip circumference. Always check the specific brand's size chart since sizing varies significantly between manufacturers.
How do international bikini sizes compare (US, EU, UK)?
International bikini sizing varies considerably across regions. US sizes typically range from 0 to 20+ or use XS through XXL. European (EU) sizes use numeric systems starting around 34 and going up to 46 or higher, with each size corresponding to specific centimeter measurements. UK sizes are similar to US sizes but offset by about 4 numbers for dresses (a US 8 is roughly a UK 12). Australian sizes are also offset from US sizes. For bikini tops sized as bras, US and UK cup sizes differ above D — the UK uses DD, E, F while the US uses DD, DDD, G. European bra sizing uses different band numbers entirely. Always consult the specific brand's conversion chart.
What bikini styles are best for different body shapes?
Different bikini styles flatter different body shapes. For hourglass figures (balanced bust and hips with a defined waist), most styles work well, especially those that highlight the waist. Pear shapes (wider hips than bust) benefit from attention-drawing tops like ruffles or bright colors paired with solid-colored, higher-cut bottoms. Inverted triangle shapes (broader shoulders and bust) look great in halter tops that provide support and bottoms with details like side ties or patterns that draw the eye downward. Athletic or rectangle shapes can create curves with ruched tops, push-up styles, and bottoms with side ties. Fuller figures often find supportive underwire tops and high-waisted bottoms both comfortable and flattering.
How should a bikini fit properly?
A properly fitting bikini should feel secure and comfortable without digging into the skin or leaving marks. The bikini top should support your bust without gapping, wrinkling, or spilling over. Straps should stay in place without sliding or cutting into the shoulders. The band should be level all around and firm enough that only two fingers fit underneath. For bottoms, the waistband should sit flat without rolling or digging in, and the leg openings should lie smoothly without cutting into the thighs. There should be adequate coverage without excess bunching of fabric. The fabric should lie flat against the skin. When trying on bikinis, test movement by bending and reaching to ensure everything stays in place during activity.
How do I interpret the result?
Results are displayed with a label and unit to help you understand the output. Many calculators include a short explanation or classification below the result (for example, a BMI category or risk level). Refer to the worked examples section on this page for real-world context.