plannedparenthood:

Someone asked us:

How effective is pulling out compared to using a condom and not pulling out?

We get these kinds of questions all the time, and the reality is they’re very difficult to answer because the effectiveness of birth control has a lot to do with how well people use it — a method doesn’t work as well if you mess it up (putting the condom on incorrectly or not pulling out before ejaculation, for example). And “messing it up” is the number one reason birth control fails.

But let’s get down to the nitty gritty and talk numbers (remember, these numbers aren’t exact and vary depending on how well you use your method):

For every 100 people who use withdrawal (pulling the penis out and ejaculating away from your partner’s vulva/vagina), 27 will become pregnant each year if they don’t always do it correctly. With perfect use, that number drops to 4 out of 100, but withdrawal is a VERY difficult method of birth control to use perfectly. The ejaculator needs to know their body, have lots of self-control, and be able and willing to pull out in time, every time. And while pre-ejaculate (pre-cum) does not usually contain sperm, sometimes it actually does — and it only takes one little sperm to cause a pregnancy. Long story short: withdrawal leaves a lot up to chance, but it’s more effective than many realize if used correctly.

For every 100 people who use condoms, 18 will become pregnant if they don’t always use them correctly. 2 out of 100 will get pregnant even with perfect use. Making sure you use condoms correctly — storing them in a cool, dry place, checking the expiration date, rolling them on the right way, adding water-based or silicone lubricant, etc. — will increase their effectiveness. 

Again, it’s impossible to predict exactly how effective each method will be for each person, but condoms come out the overall winner here. And condoms are the ONLY method of birth control that also prevents STDs, including HIV. Regardless of your pregnancy risk and/or whether or not you’re using another method of contraception, condoms are always a good idea. 

If you’re totally set on using withdrawal or condoms for pregnancy prevention, the safest way to go would be to use them together (wear a condom and also pull out before ejaculation). Ejaculating outside of your partner always reduces the chances of pregnancy, and condoms protect you against STDs and act as a backup in case pulling out doesn’t go as planned.

-Kendall at Planned Parenthood

Bolding mine.