Eli5: Condom Effectiveness


What does it mean when the statistics say that condoms are, at best, 98% effective.

It sounds like 1/50 times a condom is used, it won’t prevent pregnancy. But this doesn’t seem right because those stats wouldn’t be worth the risk.

In: 1235

50 couples using a new condom every time as their sole contraception, after 1 year, one of those couples will get pregnant.

It’s not 2% after using a single condom. It’s 2% after a year of using a new condom every time that they have sex.

Edit: clarified so people stop making the same comment about using the same condom for a year.

The statistic means that if a couple use condoms for a year, there is a 2% chance of pregnancy during the year

2% is thr people who break the condom


Just to add, the 98% is with “perfect use”. More “typical use” effectiveness is anywhere from 80-85% effective.

Not great.

Effectiveness statistics are not per use. In the 95% statistic given, this means that five couples out of one hundred will have a pregnancy during a year even if they use condoms perfectly.