Choosing the Right Swimsuit Size
Swimsuit sizes are based on body measurements including bust, waist, and hips for women, waist and hip for men, and height or age for children. Women's swimsuits typically range from XS to 3XL or numerical sizes 0 to 22, while men's swim trunks use waist measurements from 28 to 46 inches or letter sizes XS to 2XL. Kids swimwear is sized by age and height, from toddler 2T to youth 16. Choosing the right size depends on accurate measurements, understanding brand sizing variations, and considering the style and fit of the swimsuit. A size that is too small causes discomfort and movement restriction, while one that is too large sags and may come off in water.
Swimsuit sizing is not standardized across brands, with significant variations in fit even for the same labeled size. European brands often run smaller than American brands, and athletic or competitive swimwear tends to fit tighter than recreational styles. Always consult the specific brand's size chart and measure yourself before ordering online. Most brands provide measurement guides for bust, waist, hips, and torso length to ensure proper fit. When between sizes, consider the swimsuit style: size up for fuller coverage styles like one pieces, and size down for minimal styles like bikinis or briefs that benefit from a snugger fit.
History and Standards in Swimsuit Sizing
Swimsuit sizing evolved alongside changing fashion and modesty standards. Early 20th century swimwear was loose and voluminous, with sizing based on general small, medium, and large categories. As swimsuits became more form fitting in the 1940s and 1950s, sizing became more precise with measurements for bust, waist, and hips. The bikini, introduced in 1946, led to separate top and bottom sizing, with tops often sized by bra cup and band sizes. Modern swimwear combines traditional dress sizes with athletic sizing systems.
There is no universal standard for swimsuit sizing, though most American brands follow similar conventions based on dress size equivalents. A women's size 8 typically corresponds to a medium, with a 36 inch bust, 28 inch waist, and 38 inch hips. Men's sizing is more consistent, based on waist measurement in inches. International sizing adds complexity, with European sizes running 4 to 6 sizes higher than US sizes. A US size 8 equals a European size 40. Australian sizing is similar to US, while UK sizing falls between US and European standards.
Common Swimsuit Sizes Explained
A women's XS or size 0 to 2 fits a 32 to 33 inch bust, 24 to 25 inch waist, and 34 to 35 inch hips. This is the smallest adult size and suits petite builds. A small or size 4 to 6 accommodates a 34 to 35 inch bust, 26 to 27 inch waist, and 36 to 37 inch hips, fitting average petite to small framed women. A medium or size 8 to 10 is the most common size, with 36 to 37 inch bust, 28 to 29 inch waist, and 38 to 39 inch hips.
A large or size 12 to 14 fits 38 to 40 inch bust, 30 to 32 inch waist, and 40 to 42 inch hips. An XL or size 16 to 18 suits 42 to 44 inch bust, 34 to 36 inch waist, and 44 to 46 inch hips. Plus sizes 2XL and 3XL accommodate measurements above 46 inches, with some brands offering sizes up to 6XL for bust measurements over 60 inches. Men's sizes are simpler, with S fitting 30 to 32 inch waists, M for 32 to 34, L for 36 to 38, and XL for 40 to 42 inches.
How to Measure for Swimsuit Sizing
To measure bust, wrap a tape measure around the fullest part of your chest, keeping it parallel to the floor and snug but not tight. For waist, measure around the narrowest part of your natural waistline, typically above the belly button. For hips, measure around the fullest part of your hips and buttocks. Stand straight and do not pull the tape tight. Record measurements in inches or centimeters and compare to the brand's size chart. For women's one piece swimsuits, torso length also matters: measure from the top of your shoulder, through the legs, to the same point on the opposite shoulder.
Men should measure waist at the point where they normally wear shorts, typically at or slightly below the belly button. Hip measurement is taken around the fullest part. For kids, height and weight are the primary factors, though chest, waist, and hip measurements provide better accuracy. Kids grow quickly, so remeasure every few months and size up if the child is at the upper end of a size range. When in doubt, try the swimsuit on if possible, as fit varies by style, fabric stretch, and brand.
Bikini vs One Piece Sizing Differences
Bikinis often have separate sizing for tops and bottoms, with tops sized by bra cup and band like 32B or 34D, and bottoms sized XS to XL or by numerical dress size. This allows mixing sizes for better fit, as many women have different proportions on top and bottom. Triangle and bandeau bikini tops have less structure and often come in S, M, L with adjustable ties, while underwire or molded cup tops use bra sizing for better support. Bikini bottoms are sized by hip measurement, with low rise styles fitting lower on the hips and high waist styles sitting at the natural waistline.
One piece swimsuits are sized by overall body measurements and cannot be customized for different top and bottom sizes. If you are between sizes or have proportional differences, one pieces may not fit as well as separates. However, modern one pieces often have adjustable straps, removable pads, and stretchy fabrics that accommodate a range of sizes. Tankini tops and swim skirts combine the coverage of a one piece with the flexibility of separates, allowing you to mix sizes for a custom fit.
Men's Swim Trunk Styles and Sizing
Men's swim trunks come in several styles with slight sizing differences. Board shorts are longer, typically hitting the knee, and have a looser fit with a drawstring waist. They are sized by waist measurement and fit like casual shorts. Swim trunks or swim shorts are mid thigh length and fit more snugly, often with an elastic waist and inner mesh lining. They use the same waist sizing but fit closer to the body. Swim briefs or speedos are tight fitting and sized by waist and hip measurements, ranging from 28 to 40 inches.
Jammers are knee length competitive swimwear that fits like compression shorts, sized S to XL based on waist and hip. They are designed for swimming performance with minimal drag. For casual wear, most men choose board shorts or swim trunks in their regular pants waist size or one size larger for a relaxed fit. For athletic or competitive swimming, choose a size that fits snugly without restricting movement, often one size smaller than casual clothing to reduce water resistance.
Kids Swimwear Sizing and Growth Considerations
Kids swimsuit sizes are based on age and height, with some brands adding weight ranges. A 2T to 3T swimsuit fits toddlers 2 to 3 years old, typically 33 to 38 inches tall. A 4T to 5T fits 4 to 5 year olds, 39 to 44 inches tall. XS for kids fits ages 6 to 7, S fits 8 to 10, M fits 10 to 12, and L fits 14 to 16. These ranges are approximate, as children grow at different rates. Always check height and weight charts for the specific brand.
For rapidly growing kids, consider sizing up, especially if buying early in the season. A slightly large swimsuit worn with a drawstring or adjustable straps will fit longer than one that is already snug. However, avoid going too large, as excess fabric can be a safety hazard in water. Swim diapers for babies and toddlers are sized by weight, from small for 10 to 18 pounds to large for 32 pounds and up. Rash guards for sun protection are sized similarly to regular clothing, with more room for movement and layering.
Fabric Stretch and Fit Considerations
Swimsuit fabrics contain spandex or elastane for stretch, typically 10 to 30 percent. More stretch allows a swimsuit to fit a wider range of sizes but may also mean the suit loosens over time, especially when exposed to chlorine, salt water, and sunlight. A well fitting swimsuit should feel snug when dry and slightly less tight when wet, as water weight and movement will stretch the fabric. If a swimsuit feels loose when dry, it will sag when wet and may not provide adequate support or coverage.
Lined swimsuits have an extra layer of fabric for opacity and modesty. Lining adds thickness and reduces stretch slightly, so lined suits may fit more snugly than unlined. Compression swimwear, used for athletic swimming, has higher spandex content and fits very tight to reduce drag and provide muscle support. It should feel restrictive when dry and form fitting when wet. Recreational swimwear has moderate stretch and should feel comfortable for extended wear, not cutting into skin or causing restriction.
Brand Variations and International Sizing
Swimsuit sizing varies significantly by brand and country of origin. American brands like Speedo USA, TYR, and Lands End typically run true to size based on US dress sizes. European brands like Arena and Seafolly often run smaller, requiring you to size up one or two sizes. Australian brands tend to run similar to US sizing. Always consult the brand's specific size chart and read customer reviews for fit feedback. Many online retailers include comments on whether items run small, large, or true to size.
International size conversions are approximate. A US women's size 8 is roughly UK size 12, EU size 40, and AU size 12. Men's sizing is more consistent internationally, with waist measurements in inches or centimeters providing a direct conversion. When ordering from international retailers, use measurements in centimeters if provided, as these are more precise than converted sizes. Some brands offer petite, tall, or long torso versions of the same size for better fit across different body proportions.
Practical Tips for Swimsuit Size Selection
Measure yourself accurately before shopping, especially when buying online. Use a flexible tape measure and have someone help with hard to reach areas like torso length. Compare your measurements to the brand's size chart, not just the size label, as sizes vary. If between sizes, consider the swimsuit style and your personal preference: size up for more coverage and comfort, or size down for a sleeker, more athletic fit. For swimsuits with adjustable features like ties, straps, or clasps, you have more flexibility to customize fit.
Finally, remember that swimsuits stretch over time with wear and exposure to water and sun. A new swimsuit should feel snug but not uncomfortable. If it feels loose initially, it will only get looser with use. Rinse swimsuits in cold water after each use and avoid hot tubs and chlorinated pools when possible, as heat and chemicals degrade elastic fibers. A swimsuit size guide with detailed measurements, brand comparisons, and fit tips helps you choose confidently, ensuring your swimwear fits well, feels comfortable, and lasts multiple seasons.