External condoms are about 87% effective with typical use (a 13% yearly failure rate per the CDC) and about 98% effective with perfect use.
Internal condoms are lower, at a 21% typical-use failure rate. Most real-world failures trace to use errors: late application, early removal, breakage, oil-based lubricants weakening latex, expired stock, or heat damage from wallets and cars. The fix-list is short: check dates, pinch the tip, water or silicone-based lube only with latex, a fresh condom every time, and hold the base on the way out. Condoms are also the only contraceptive that reduces STI risk, including HIV, which is why the standard advice is pairing: condoms plus a more pregnancy-reliable method like the pill, implant, or IUD covers both jobs at once. Note that natural or lambskin condoms prevent pregnancy but do not block STIs the way latex does. If a condom breaks or slips, emergency contraception can prevent pregnancy for up to 5 days after unprotected sex.
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Common questions
How effective are condoms?
External (male) condoms are about 87% effective with typical use: the CDC puts their typical-use failure rate at 13%, meaning about 13 in 100 couples using condoms for a year will see a pregnancy. With perfect use, every time, put on before any genital contact, no tears or slips, effectiveness reaches about 98%. Internal (female) condoms run lower, at 79% typical effectiveness (21% failure rate). The gap between typical and perfect comes from real-world errors: putting a condom on late, taking it off early, breakage from oil-based lubricant degrading latex, using an expired condom, or storing them in hot places like a wallet or glove box. Latex condoms carry a second job no other method does: they help protect against HIV and other STIs, which is why clinicians recommend pairing condoms with another contraceptive rather than choosing between them. A few rules that close most of the gap: check the expiration date, pinch the tip before rolling on, use water-based or silicone lube only with latex, one condom per erection, and hold the base during withdrawal. If a condom breaks, emergency contraception works up to 5 days after.