How to measure for the perfect fit

Gather Your Supplies. You'll need a piece of string and a ruler to get your measurement. We recommend using a string instead of trying to use a soft tape measure.

Measure. Wrap the string around your penis and behind your balls. Mark the string where it meets. You want the string quite snug. You should be able to just fit a finger between your skin and the string when you're soft. And it should be comfortably tight when you're hard so that you can't fit in a finger. You may want to measure both soft and hard to double-check your size.

Determine Your Size. Measure the distance from the end of the string to the mark.  This is the circumference.  Use the handy table below to get your size.

Circumference Ring Diameter
13.0-14.5cm (5.0-5.75in) 40mm (~1.6in)
14.5-16.5cm (5.75-6.25in) 45mm (~1.8in)
16.5-18.0cm (6.25-7.0in) 50mm (~2.0in)
18.0-19.5cm (7.0-7.75in) 55mm (~2.2in)

Tips For Measuring

  • Most guys are in the 40mm-50mm range.
  • 55mm is a pretty big ring. So if you're not bigger than average, try measuring again and make sure you pull the string tight.
  • If you have a good-fitting round ring, MEASURE ANYWAY. You may find your Primal ring size is 5mm (~.2 in) smaller than your round ring size. Our keyhole shape fits a bit looser than a round ring with the same diameter.
  • Measure twice!  Due to the intimate nature of these rings, we can't accept returns or exchanges.
Remember: Safety first! Do not wear a ring that is too tight, and remove the ring immediately if you feel discomfort, a sensation of coolness, observe any changes in color, bleeding, or feel tingling or numbness. If in doubt, take it off. Men with pre-existing genital conditions or injuries, or those taking anticoagulants should consult their physician prior to use. Cock rings should not be worn for more than 30 minutes, and you should not sleep in a ring.