Once a condom has sperm in it, be careful!

How to figure out your condom size. To avoid things like condom flips, slips, and leaks, wrap your thumb and index finger. You can figure out the width of your penis the same way you’d determine the diameter of a circle. To do this, divide your girth measurement by 3.14.

Use a toilet paper roll to measure your penis girth. If you take all the condoms widely available on the market and sort them out by their size, you get four distinct. Use the following steps to take an accurate measurement of the penis and find the best condom fit:

The resulting number is your width. The average erect penis is 5.16 inches long and 4.59 inches wide, according to a review of 15,500 men's penises. Finding your condom size is not rocket science so let's not pretend that it is.

This gets you your condom nominal width in millimeters (mm).