PREDICTION Size Guide
Find your best fit in PREDICTION boxer briefs. Our sizing is based on waist measurement, but PREDICTION also gives you two leg-fit options: Standard and Slim. Standard and Slim use the same waist size — the difference is the thigh and leg opening fit.
Start with your waist size.
Then choose the leg fit that feels right for your thigh shape and comfort preference.
| Size | Waist | Inseam Thigh Length |
Leg Fit Thigh Fit |
|---|---|---|---|
| Medium | 30–33 in |
8"
— Ad Astra
4" — Ryder |
Standard (Relaxed)
Slim (Tailored) |
| Large | 33–36 in |
8"
— Ad Astra
4" — Ryder |
Standard (Relaxed)
Slim (Tailored) |
| X-Large | 36–39 in |
8"
— Ad Astra
4" — Ryder |
Standard (Relaxed)
Slim (Tailored) |
Standard and Slim use the SAME waist measurement.
Slim does not mean a smaller waist —
only a slimmer thigh and leg opening fit.
Built for different thigh profiles.
Most underwear brands only change the waist size. PREDICTION also lets you choose how the leg fits.
Relaxed comfort.
Designed for everyday comfort with a more relaxed feel around the thigh. Best if you prefer more room or have larger thighs.
Closer, tailored fit.
Same waist size, but with a slimmer leg opening for a closer fit. Best if regular boxer briefs feel loose around your legs.
Relaxed or Tailored
Find what feels just right. Choose Standard for more room, or Slim for a closer hold.
Ad Astra or Ryder?
Both are built with PREDICTION utility, but each series is designed for a different carry style.
Ad Astra
Maximum coverage and secure carry with dual-pocket utility.
Ryder
Lightweight everyday carry with a shorter, easy-moving profile.
Still not sure?
Start with your normal waist size. Choose Standard if you want more room around the thigh. Choose Slim if you prefer a closer, more tailored leg fit.