Choosing the Right Underwear Size
Underwear sizes are based on waist and hip measurements, with men's underwear primarily sized by waist and women's by hips. Men's sizes range from XS with a 26 to 28 inch waist to 3XL with a 48 inch waist or larger. Women's sizes range from XS or size 2 to 4 with 24 to 26 inch waists to 3XL or size 22 to 24 with 40 to 42 inch waists. Choosing the right size depends on accurate measurements, understanding the underwear style, and personal fit preferences. Underwear that is too small digs in and causes discomfort, while underwear that is too large bunches, rides up, and provides poor support.
Unlike outerwear, underwear fit is critical for comfort and function. Most people wear underwear 12 to 16 hours per day, making proper fit essential. Sizing varies between brands, with some running small and others generous. Athletic and performance underwear tends to fit tighter than everyday cotton styles. Elasticity and fabric content also affect fit, with high spandex blends stretching more than pure cotton. Always measure yourself and consult brand specific size charts, especially when trying new brands or ordering online. When between sizes, consider the style: size up for relaxed fit boxers, size down for snug briefs or athletic styles.
History and Standards in Underwear Sizing
Modern underwear sizing evolved in the early 20th century as mass production replaced custom tailored undergarments. Early sizing was inconsistent, with manufacturers using proprietary systems based on chest, waist, or overall height. By the 1950s, standardized sizing emerged using waist measurements in inches for men and dress sizes for women. Men's sizing has remained relatively consistent, while women's sizing still varies significantly between brands due to diverse body shapes and style preferences.
The shift from woven fabrics to knits with elastic in the mid 20th century changed fit expectations. Elastic waistbands allowed a single size to fit a range of measurements, leading to S, M, L sizing alongside numerical waist sizes. Today, most men's underwear uses both systems: waist measurements like 32 to 34 inches and letter sizes like M are often equivalent. Women's underwear primarily uses letter sizes or dress size ranges like 10 to 12, though some brands provide waist and hip measurements for precision. There is no universal standard, making it essential to check each brand's specific chart.
Common Underwear Sizes Explained
A men's small fits waists 28 to 30 inches and hips 32 to 34 inches, suiting slim to average builds. A medium fits 32 to 34 inch waists and 36 to 38 inch hips, the most common size for adult men. A large accommodates 36 to 38 inch waists and 40 to 42 inch hips, fitting larger or athletic builds. XL and 2XL sizes extend to 46 inch waists or more, providing options for all body types. Men who lift weights or have muscular thighs may need to size up for comfort in fitted styles like boxer briefs.
Women's XS or size 2 to 4 fits 24 to 26 inch waists and 33 to 35 inch hips, suiting petite frames. Small or size 6 to 8 accommodates 26 to 28 inch waists and 35 to 37 inch hips. Medium or size 10 to 12 is the most common, fitting 28 to 30 inch waists and 37 to 39 inch hips. Large and XL sizes fit waists up to 38 inches and hips up to 47 inches, with plus sizes extending further. Women's underwear sizing is complicated by varying rises, with low rise styles sized primarily by hips and high waist styles requiring accurate waist measurements.
How to Measure for Underwear Sizing
To measure waist for underwear, wrap a tape measure around your natural waistline, typically at or just above the belly button. Do not pull tight; the tape should sit comfortably against your skin. For hip measurement, wrap the tape around the fullest part of your hips and buttocks, usually 7 to 9 inches below the waist. Stand straight and relax your stomach for accurate measurements. Record in inches or centimeters and compare to the brand's size chart. If your waist and hip measurements fall into different size categories, choose based on the style: hip measurement for low rise styles, waist for high rise.
Men should measure where they typically wear pants, which may be slightly below the natural waist. For boxer briefs and briefs, measure around the fullest part of the hips as well, as thigh circumference affects fit. Athletic men with large thighs may need to size up even if the waist fits, as tight leg openings cause discomfort. Remeasure every few years, as body shape changes with age, weight fluctuation, and fitness level. Underwear that fit well five years ago may no longer be the correct size.
Men's Underwear Styles and Sizing
Briefs are classic underwear with full front coverage, a Y shaped fly, and elastic leg openings. They fit snugly and are sized primarily by waist, with sizes running true to measurement. Briefs provide support and work well under dress pants. Boxers are loose fitting shorts style underwear with a button or elastic fly. They are sized by waist but fit loosely, so sizing up is common for comfort. Boxers offer minimal support but maximum breathability and freedom of movement.
Boxer briefs combine the length of boxers with the snug fit of briefs, extending mid thigh. They are the most popular men's style and are sized by waist and hip. Fit is closer to body than boxers, so choose your true size or size up if you have muscular thighs. Trunks are shorter than boxer briefs, ending just below the hip, and fit similarly. They work well for active wear and under slim fit pants. Performance or athletic underwear uses moisture wicking fabrics and compression fits, often running smaller than casual styles. Size based on brand charts and consider sizing up for all day comfort.
Women's Underwear Styles and Sizing
Bikini or low rise panties sit on the hips below the natural waist. They are sized primarily by hip measurement and provide moderate coverage. This is a popular style for everyday wear and works under low rise jeans. Hipster panties have slightly more coverage than bikinis, extending higher on the hips with a lower leg opening. They are sized by hip and offer a balance of coverage and comfort without visible panty lines under most clothing.
Brief or full coverage panties sit at or above the natural waist with full back coverage. They are sized by both waist and hip, as the waistband sits higher. Briefs provide maximum comfort and support, popular among older women and for postpartum wear. High waist or control panties extend above the navel, often with shapewear features. They are sized by waist and designed to smooth and shape the stomach. These run tighter than regular briefs and may require sizing up. Thongs and G strings provide minimal coverage and are sized by hip, with fit focused on the waistband and minimal fabric at the back.
Fabric and Stretch Considerations
Underwear fabric affects sizing and fit. Cotton underwear has minimal stretch and should fit comfortably when new, as it will not stretch significantly with wear. Cotton blends with 5 to 10 percent spandex offer slight stretch for comfort. Modal and bamboo fabrics are soft and stretchy, conforming to body shape and allowing a single size to fit a wider range. Microfiber and synthetic blends often contain 15 to 30 percent spandex, providing significant stretch and a sleek fit under clothing.
Performance fabrics for athletic or moisture wicking underwear are designed to fit snugly and may feel tight initially. They stretch with body heat and movement, so size based on measurements rather than trying to achieve a loose fit. Compression underwear for sports fits very tight and may require sizing up for all day wear. Lace and delicate fabrics stretch less than knits, so lace trimmed styles may fit smaller than the same size in cotton or microfiber. Always check fabric content and stretch when selecting size.
Brand Variations and Fit Differences
Underwear sizing varies significantly by brand. Budget brands often use generous sizing to appeal to a wider audience, while premium and European brands tend to run smaller. Athletic brands like Under Armour and Nike size based on sports performance fits, often tighter than casual brands like Hanes or Fruit of the Loom. Luxury brands may use European sizing, with a US medium equivalent to a European large. Always consult the specific brand's size chart and read customer reviews for fit feedback.
Some brands offer petite, regular, and tall options within the same size, affecting leg length in boxer briefs or trunk styles. Others provide short, regular, and long rise options for women's panties, accommodating different torso lengths. If you fall between sizes consistently in one brand, try a different brand known for smaller or larger fits rather than forcing yourself into an uncomfortable size. Fit preferences also vary: some people prefer snug underwear, others loose, so personal comfort matters as much as technical sizing.
Sizing for Specialty Underwear
Maternity underwear for pregnant women is sized by pre pregnancy size but designed with expandable panels or low rise cuts to accommodate growing bellies. Size based on your usual size at the start of pregnancy, not your current size. Postpartum underwear often runs larger and higher waisted for comfort and to hold pads. Athletic compression shorts are sized by waist and inseam, with tight fits to reduce muscle fatigue. Size based on exact measurements, as compression only works if the fit is snug.
Thermal underwear for cold weather is often sized to layer under clothing, so it runs true to size or slightly fitted. Long johns are sized by waist and inseam like pants. Adaptive underwear for people with limited mobility or medical needs often uses side closures or extra stretch, with sizing based on waist and hip but more forgiving fits. Always check product descriptions for special sizing notes on functional or medical garments.
Practical Tips for Underwear Size Selection
Measure yourself accurately and compare to the brand's size chart, not generic charts, as sizing varies. If purchasing in store, buy one of your usual size to try, but keep the receipt in case you need to exchange. Online shoppers should order two sizes if unsure, keeping the better fit. Check return policies before ordering, especially for underwear, as some retailers do not accept returns on opened undergarments for hygiene reasons. Look for multipacks in your size once you find a brand and style that fits well, as this is more economical than buying singles.
Finally, reassess your size periodically. Weight changes of 10 pounds or more, pregnancy, aging, and changes in fitness level all affect underwear fit. Replace worn out underwear when elastic loses stretch, fabric thins, or fit becomes uncomfortable. A good rule is to replace underwear every one to two years with regular wear. An underwear size guide with detailed measurements, style explanations, and brand comparisons helps you choose confidently, ensuring your undergarments fit comfortably all day and support your daily activities without pinching, riding up, or causing visible lines under clothing.