Use your girth measurement to find your category. Note that brand labels like "Large" can vary between companies. Girth (Circumference) Nominal Width (Flat) 3.9" – 4.3" (100–110mm) Under 52mm Regular 4.3" – 4.7" (110–120mm) 52mm – 56mm Large / XL 4.7" – 5.3" (120–135mm) 56mm – 60mm XXL Over 5.3" (135mm+)
Healthline for a comprehensive list of length vs. width requirements. How to choose the right size condom | NHS which condom size to buy
Measure from the base (at the pubic bone) to the tip of the penis. Use your girth measurement to find your category