How effective is spermicide at preventing pregnancy?

There are two types of spermicide, prescription and over-the-counter options. How effective it is depends on the type you use. If over-the-counter spermicide is used alone, it is only somewhat effective—around 84% when used perfectly and 79% with typical use, that means how real people use it in real life.

In other words:

For people who use spermicide perfectly every single time for a whole year, about 16 in 100 will get pregnant when they don’t want to during the first year of using spermicide.

For people who use spermicide as people typically use it, about 22 in 100 will get pregnant when they don’t want to during the first year of using spermicide.

Prescription spermicide is more effective, 93% effective with perfect use and 86% effective with typical use.