Women’s underwear sizes run XS (24–25″ waist, 34–35.5″ hip) to 2XL (37–38″ waist, 47–48.5″ hip); men’s sizes run XS (24–28″ waist) to 2XL (42–46″ waist). A size 7 numeric equals Medium-Large, and size 8 equals Large, not Medium.
This guide breaks down the full underwear size chart for men and women, shows you how to measure at home, compares sizing across major US brands, and answers the questions people search for most.
Why Underwear Sizes Aren’t Universal
This is called vanity sizing — brands adjust numbers to flatter shoppers or match their target customer. It’s why numeric sizing (5, 6, 7…) and alpha sizing (XS, S, M…) don’t line up the same way across brands. A size 7 at one company might be labeled Large; at another, it’s Medium.
Body type, fabric stretch, and garment cut also change how a size fits. Two people with the same waist measurement can need different sizes depending on hip shape or rise (how high or low the waistband sits).
Women’s Underwear Size Chart
Most brands size women’s underwear by hip measurement first, then cross-reference waist and dress size.
Size
Waist (in)
Hip (in)
Numeric
Dress Size
XS
24–25
34–35.5
5
0–2
S
26–27
36–37.5
6
4–6
M
28–29
38–39.5
7
8–10
L
30–32
40–42
8
12–14
XL
33–36
43–46
9
16
2XL
37–38
47–48.5
10
18
3XL
38.5–40
49–51.5
11
20–22
Plus size ranges typically start at 9/2XL and extend to 14/5XL, using waist bands measured differently than alpha sizes. Petite sizing usually shortens the rise and leg opening rather than the waist number.
Men’s underwear sizing is simpler — it’s based almost entirely on waist measurement, since most styles sit at or below the natural waistline.
Size
Waist (in)
XS
24–28
S
28–32
M
32–34
L
34–38
XL
38–42
2XL
42–46
Boxer briefs and trunks run closer to the body and often fit true to this chart. Boxers and relaxed-fit briefs are looser, so many men size down for a tighter hold or size up for extra room.
Measure your natural waistline and the fullest part of your hips and seat, keeping the tape level and parallel to the floor. For most women’s styles, the hip measurement is especially important.
Bust or Chest Measurement
For bralettes, combo sets, or undershirts, measure around the fullest part of your chest, keeping the tape level under your arms.
Check the Fit
The waistband should sit flat without digging in or rolling down, while leg openings should stay flat without riding up or cutting in. Wedgies, panty lines, sagging, bulging, or deep red marks can indicate the wrong size or cut.
I am the admin and author of SizesForm, researching, verifying, and explaining measurements, dimensions, weights, and sizes in simple terms to help readers understand everyday comparisons accurately and confidently.
