How effective are condoms at preventing pregnancy?

In an absolutely perfect world, condoms are relatively effective—around 98%. But (and this is super important) in the real world, people mess up. They don’t use them 100% of the time. Or the condom breaks, or slips off. So with typical use, they’re only around 82% effective, which is a big difference.

In other words:

Of those women who use condoms exactly as directed, about 2 in 100 will experience an accidental pregnancy during the first year they use this method.

Of those women who do not use condoms exactly as directed, about 18 in 100 will experience an accidental pregnancy during the first year they use this method.