Choosing women’s underwear starts with hip and waist measurements, not dress size, since brand size charts vary widely.
Buying underwear feels simple until a supposedly correct size leaves red marks or bunches under clothes. The right pair depends on fit, fabric, and cut — all traceable to two measurements you can take in about a minute. Here’s the practical method for picking comfortable underwear, plus sizing rules brands rarely spell out.
Measure Your Waist and Hips First
Underwear size charts map primarily to hip measurement, so grab a soft tape measure and take two numbers: your natural waist at the narrowest point and your hips around the fullest part. Nike’s size guide uses exactly these two measurements. When your waist and hips suggest different sizes, follow the hip measurement — Nike’s chart explicitly advises ordering based on hips if the two point different ways. That rule holds for most brands because underwear needs to stay anchored at the hip without sliding or twisting.
Size Charts: Use Them, But Know Their Limits
Brands don’t share one universal sizing system, so always open the specific product’s chart before ordering. Fruit of the Loom’s women’s underwear chart, for example, maps sizes to hip ranges: XS (4) fits 34–35 inches, S (5) fits 36–37, M (6) fits 38–39, L (7) fits 40–41, XL (8) fits 42–43, 2XL (9) fits 44–45, and 3XL (10) fits 46–47 inches.
If you land between sizes, decide by the fit you want: Nike advises ordering the smaller size for a tighter fit or the larger for a looser one. When your hips and waist disagree, hips win the tiebreaker. The single biggest mistake is choosing by dress size alone — charts differ not just between brands but between product lines from the same company, and dress sizes don’t map cleanly to hip measurements. A medium in one athletic line may run tighter than a medium in the same brand’s cotton basics.
For premium or imported brands like SKIMS, which maps XXS through 4X across US, UK/AUS, EU, IT, FR, and JP systems, confirm which regional chart you’re reading before you order.
How Underwear Should Fit Once It’s On
Fit checks beat any number on a chart. Properly fitting underwear has no excess fabric pooling in the front or back, a waistband that sits flat and smooth without digging in, and leg openings that don’t pinch, roll, or leave marks. Coverage should feel even and symmetrical on both sides. If your waistband leaves indentations or the leg elastic presses into your thighs, size up. If the fabric bunches or sags through the day, size down. The crotch and seat areas should hold their position without constant adjusting — that’s the signal a cut doesn’t match your body shape.
Different cuts suit different needs. Briefs and boyshorts offer fuller coverage; hipsters sit lower; thongs and bikinis minimize visible lines. Choose the cut that matches the outfit and your comfort — snug-but-not-tight is the goal across every style.
Fabric, Care, and Common Mistakes
Fabric determines whether underwear feels breathable through a workday or traps heat by noon. Comfort, breathability, and softness should drive the choice, and organic cotton is a solid default since it’s gentle against sensitive skin. Save synthetic blends for workouts or when you need moisture-wicking performance during exercise.
When you’re ready to shop, our roundup of barely-there panties that disappear under clothes covers the best options for seamless, invisible wear.
Avoid underwear that compresses your waist, leaves thigh indentations, or bunches fabric anywhere — those signs mean a size or cut mismatch, not a body problem. Wash underwear in cold water and skip the dryer when possible, since heat breaks down elastic and stretched-out waistbands defeat even a perfect initial fit. Pay attention to the fit each time you buy, as body measurements change and brands tweak their cuts between seasons.
| Fit Signal | What It Means | Fix |
|---|---|---|
| Waistband digs in or marks skin | Too small or too tight | Size up or choose a lower-rise cut |
| Leg openings pinch or roll | Wrong cut for your shape | Try a different style like briefs instead of thongs |
| Excess fabric in crotch or seat | Too large or wrong rise | Size down or switch to a higher-rise style |
| Waistband sags or slides down | Too large | Size down or adjust to hip measurement |
| Underwear bunches or twists | Wrong cut for body shape | Try fuller-coverage cuts like boyshorts |
Wirecutter’s testing of women’s underwear reinforces that no single brand works for everyone — fit varies by body type, and the best pair for one person may disappoint another. That’s why the measurement and fit-check method above beats relying on any one brand’s reputation or your usual dress size.
FAQs
What if my waist and hip measurements fall in different sizes?
Use the hip measurement to choose your size. Underwear anchors around the hips, so a pair sized for your hips will stay in place, while sizing by waist alone risks underwear that slides down or twists through the day.
Should I size up for comfort?
Not automatically. Size up only if the waistband digs in or leg openings leave marks. If the fit feels snug but doesn’t create indentations or discomfort, that’s correct — underwear should fit close to the body without compressing it.
Why does the same size fit differently across brands?
Each brand uses different fit models and measurement charts. One company’s medium may match another’s small, and athletic lines often run tighter than cotton basics. Always check the specific product’s chart rather than assuming your size transfers between brands.
References & Sources
- Nike. “Underwear Size Guide.” Explains waist/hip measurement method and between-size guidance.
- Fruit of the Loom. “Women’s Underwear Size Chart.” Maps sizes 4/XS through 10/3XL to specific hip ranges.
- Wirecutter (NYTimes). “The Best Women’s Underwear.” Notes that fit varies by body type across brands.