Men's Underwear Size Calculator
One waist measurement finds your underwear size from S to XXL — with EU equivalents and fit notes for briefs, boxers and trunks.
How men's underwear sizing works
Men's underwear sizes follow a single measurement: your waist. Match your waist measurement to the chart below to get your letter size, with the EU numeric equivalent used by European brands.
| Size | Waist (inches) | EU size |
|---|---|---|
| S | 28–30 | 44–46 |
| M | 31–33 | 48–50 |
| L | 34–36 | 52 |
| XL | 37–39 | 54 |
| XXL | 40–43 | 56–58 |
The same waist range applies across styles — briefs, boxer briefs, trunks and boxers — but each style fits that range differently, so the cut matters as much as the size.
Measuring & fit tips
- Measure at the waistband line. Wrap the tape where your underwear actually sits — usually just below the navel, not at your trouser waist.
- Between sizes? Size up. A pinching waistband never gets more comfortable; slightly roomier elastic still holds its shape.
- Match the style to your build. Briefs suit slimmer builds and active days; boxer briefs add thigh coverage; loose boxers are the most forgiving fit.
- Watch the fabric. Pure cotton can shrink slightly in the wash; cotton-elastane blends hold their shape and stretch better.
- Replace tired pairs. When the waistband rolls or the elastic stops snapping back, the size no longer fits — refresh the drawer.
Frequently asked questions
Is underwear size the same as trouser size?
Usually, yes — both are based on your waist measurement in inches, so a 34-inch waist typically means size L underwear and 34-inch trousers. Vanity sizing in trousers can throw this off, so the tape measure wins.
Should men's underwear be tight or loose?
Snug but not restrictive. The waistband should sit flat without digging in, and the pouch should support without compression. If you get red marks on your skin after wearing them, size up.
Do boxers, briefs and trunks share the same sizing?
The size label means the same waist range, but the fit differs: boxers are forgiving through the leg, while briefs and trunks need a precise waist and rise. If you're between sizes, size up in briefs and trunks.
What does the EU underwear size mean?
European brands label underwear 44–58 instead of S–XXL — it's roughly your waist in centimetres divided by two. A 34-inch (86 cm) waist is about an EU 52. The chart above maps each size.