Support yourself during athletics by wearing the appropriate size of jock strap. Jock straps prevent unnecessary injuries for men while playing sports. The elastic band accommodates a wide variety of waist sizes and the cup sizes vary for comfort. Both men and boys wear jock straps, which fit similarly to underwear, either over undergarments or beneath undergarments. Choosing the right size is just like picking out a new pair of boxers or briefs — you want the fit to be comfortable and wearable for long periods of time.

Determine if you will wear the strap under or over your boxers or briefs. Wearing the jock strap over the underwear may push the waist size up one, if you are on the cusp of two sizes. Choose boxers or briefs that fit tightly, not loosely, if wearing over the undergarments.

Measure your waist for an accurate size. Use a flexible tape measure and wrap it around the widest part of your waist. Use this measurement to determine if your jock strap is a small, medium or large. Take your measurements while wearing boxers or briefs if you will be wearing the jock strap over undergarments.

Match your waist size to the jock strap size chart. Most jock strap size charts are located on the package; however, a small waist for men is typically a 26-32. A medium is 34-38. A large is 40-44. Child jock straps will be the same size as their underwear. Go up one size if the boy is wearing the strap over underwear.

Purchase the cup size separately if the items do not come pre-packaged together. Typically, the cup is sold with the size of the jock strap; however, if the cup is not included, purchase the cup size depending on your preference of small, medium or large.