The girth is more important than the length because the condom will not adjust much to allow for a thicker or slimmer penis. However, the length can be flexible. A condom that is too long can be rolled down at the base, while a condom that doesn’t reach the base of the penis still offers adequate protection if it correctly fits your girth. [2] X Research source

You may be tempted to add a little slack to increase your measurement, but remember that this opens you up to risk because your condom won’t fit well. No one but you has to know your number, so be accurate.

This is your girth measurement.

While it’s possible to find a condom that fits well without measuring the length of your penis, most condoms include the length of the condom on the box. Knowing your length will allow you to choose between brands.

If you have a curved penis, use a soft ruler or a measuring tape and push it against the curve to get the accurate length. [8] X Research source

For example, if you are choosing between two lengths and your penis is 5. 25 inches (13. 3 cm), you may choose a condom that has a length measurement of 4 to 6 inches (10 to 15 cm) rather than one with a length of 5 to 7 inches (13 to 18 cm).

You can use the length measurement of your penis to choose a brand with a similar length.

When choosing between brands, don’t forget that you can look on the box to find the length of the condom.

If you are choosing between brands, remember to compare your length to the condom length listed on the box. Buying condoms that are too large is a common tendency among men. However, remember that you are exposing your partner and yourself to the consequences of unprotected sex if you are intentionally choosing condoms that are too big. Only buy large condoms if your girth is too thick for standard condoms, based on the measurement.

It’s okay to have extra length of condom rolled up at the base of your penis. If your girth requires a condom size that is longer than your length, just roll up the extra at the top until it fits. [14] X Research source

Some condoms will fit tightly, while others may be tight near the base but loose over the top of the penis.