Choosing the Right Swimsuit Size
Swimsuit sizing varies significantly between brands, styles, and regions. Women's swimsuits are typically sized using letters like XS, S, M, L, and XL, or numeric sizes such as 0-18 in the US. Men's swimwear uses waist measurements in inches or small to extra-large letter sizing. Unlike regular clothing, swimsuits must fit snugly when dry because they stretch when wet. A swimsuit that feels slightly tight in the fitting room will fit perfectly in the water, while one that feels comfortable when dry will become loose and saggy when wet.
The fit requirements differ by swimsuit style. One-piece swimsuits need to fit the bust, waist, and hips simultaneously, making them more challenging to size than two-piece suits. Bikinis allow mixing top and bottom sizes, which is ideal for women whose bust and hip sizes differ. Athletic or competition swimsuits are designed for compression and durability, while fashion swimsuits prioritize appearance and may use lighter fabrics that stretch more. Always check the specific brand's size chart rather than assuming your usual clothing size will translate directly.
History and Standards in Swimsuit Sizing
Swimwear sizing evolved alongside changing social norms about beach attire. In the early 1900s, swimsuits were wool garments that covered most of the body and were sized simply as small, medium, or large. The bikini was introduced in 1946, creating the need for separate top and bottom sizing. By the 1960s, synthetic fabrics like nylon and spandex allowed for more fitted designs, and sizing became more precise with measurements for bust, waist, and hips.
International swimsuit sizing follows regional clothing standards but with variations. US sizes run larger than European sizes, so a US size 8 typically equals a European size 40. UK sizing adds 4 to US sizes, making a US 8 equal to a UK 12. Australian sizing generally matches UK sizing. These conversions are approximate because fabric stretch, brand fit philosophy, and style differences create variations. Some brands use their own sizing systems entirely, particularly luxury swimwear labels that may size from 1 to 5 rather than XS to XL.
Common Swimsuit Sizes Explained
Women's swimsuit sizes typically start at XS or size 0 and go up to 3X or size 24 and beyond in specialty retailers. An XS or size 0-2 fits a bust of 32-33 inches, waist of 24-25 inches, and hips of 34-35 inches. A medium or size 8-10 accommodates a 36-37 inch bust, 28-29 inch waist, and 38-39 inch hips. An XL or size 16-18 fits a 42-44 inch bust, 34-36 inch waist, and 44-46 inch hips. These measurements are guidelines, and trying on swimsuits is essential because fabric type and construction affect fit significantly.
Men's swim trunks and board shorts are sized by waist measurement. A small fits a 28-30 inch waist, medium fits 32-34 inches, large fits 36-38 inches, and XL fits 40-42 inches. Board shorts have longer inseams, typically 17-23 inches depending on size, while swim trunks have shorter 5-7 inch inseams. Some men's swimwear uses numeric waist sizing like jeans, ranging from 28 to 44 inches. These sizes assume a standard rise and hip proportion, so men with athletic builds or larger thighs may need to size up.
How to Measure for Swimsuit Sizing
To measure for a women's swimsuit, use a flexible tape measure and wear minimal clothing. For bust, measure around the fullest part of the chest, keeping the tape parallel to the floor. For waist, measure around the natural waistline, typically the narrowest part of the torso. For hips, measure around the fullest part of the buttocks. Stand naturally and do not pull the tape tight. Record measurements in inches or centimeters and compare to the brand's size chart. If measurements fall between sizes, consider the swimsuit style and fabric. High-stretch fabrics accommodate a range, while less stretchy athletic suits need precise sizing.
For men's swimwear, measure the waist at the point where you want the waistband to sit, typically at the natural waist or slightly below. Men's swim trunks sit at various rises, so some prefer low-rise styles that sit on the hips, while others like higher waistbands. Measure the inseam if you prefer specific leg lengths, especially for board shorts where inseam affects coverage and style. Athletic men should also measure the thigh circumference to ensure the leg opening is not too tight.
Size Comparisons and Practical Differences
A women's size small in one brand may fit like a medium in another due to differences in cut, fabric stretch, and target market. Designer and international brands often run smaller than mass-market American brands. European brands like those from France or Italy typically size smaller and have less fabric stretch, requiring sizing up one or two sizes. Brazilian swimwear often has minimal coverage and runs very small, with their size medium fitting like a US small. Always consult each brand's specific measurements rather than assuming consistency across brands.
Men's swim trunks with elastic waists offer more size flexibility than those with drawstring-only closures. A good elastic waistband with a drawstring backup allows the swimsuit to fit snugly but adjust for comfort. Board shorts designed for surfing use Velcro and tie closures for security and fit tighter than casual swim shorts. Jammers and competition suits for men are sized by waist and inseam and must fit very snugly to reduce drag, often feeling uncomfortably tight when dry but perfect in the water.
Regional Variations and Sizing Factors
Swimwear brands often design for their home market's body proportions. American brands accommodate a wider range of bust sizes and often offer more coverage. European brands may have narrower cuts and expect a slimmer torso. Asian brands frequently run very small and may not offer extended sizes. Australian and surf brands like Speedo and Billabong design for athletic bodies and prioritize performance over fashion fit. Understanding these regional tendencies helps when shopping internationally or online.
Plus-size swimwear has expanded significantly, with many brands now offering sizes up to 3X or size 24. These suits often include features like tummy control panels, underwire support, and adjustable straps for better fit and confidence. Maternity swimwear is designed to accommodate a growing belly and changing bust size, typically using extra stretch fabric and empire waistlines. Athletic swimwear for competition is sized for minimal drag and maximum durability, using thick, compressive fabrics that feel very different from fashion swimwear.
Practical Tips for Swimsuit Selection
When trying on swimsuits, move around to test the fit. Raise your arms, bend over, and sit down to ensure the suit stays in place. For women, check that the bust is fully covered without spillage and that straps do not dig into shoulders. The leg openings should not cut into the thighs, and the back should provide adequate coverage without riding up. For one-piece suits, the torso length is crucial. If the straps feel too long or the crotch sags, the suit is too large or the torso is too long for your body. If straps pull uncomfortably or the crotch is tight, size up or try a different brand with a longer torso.
Fabric content affects fit and longevity. Suits with at least 15-20 percent spandex or elastane maintain shape and provide good stretch. Chlorine-resistant fabrics like polyester blends last longer in pools than nylon. Lined swimsuits offer better coverage and shape but may dry more slowly. Consider where you will wear the suit. Pool swimmers need chlorine-resistant fabrics, while beachgoers can use lighter, fashion-focused materials. Always rinse swimsuits in cold water after use and air dry to extend their lifespan and maintain fit.
Specialty Sizing and Customization
Some swimwear brands offer specialty sizing, such as long torso, tall, petite, or DD+ cup options. These cater to body proportions that standard sizing does not accommodate. Long torso suits add 1-2 inches to the body length, preventing uncomfortable pulling. DD+ cup bikini tops include underwire and more supportive construction. Petite sizing shortens torso length and adjusts proportions for women under 5 feet 4 inches. Athletic brands offer performance sizing with compression fits and minimal seams for competitive swimmers.
Custom swimwear is available from some brands and designers, allowing you to specify measurements for a perfect fit. This option is more expensive but worthwhile for difficult-to-fit body types or specific needs like mastectomy swimwear. When buying swimsuits online, check the return policy carefully, as many retailers do not accept returns on swimwear for hygiene reasons unless it has not been tried on or tags are still attached. A swimsuit size guide with detailed measurements and fit advice helps you choose confidently and reduces the likelihood of needing returns.