External (male) condoms are about 98% effective at preventing pregnancy with perfect use and around 87% with typical use. Just as importantly, condoms are the only method that also reduces the risk of STIs, including HIV. The large gap between perfect and typical use comes down almost entirely to how consistently and correctly they're used.
Pregnancy protection: the numbers
According to the CDC, external condoms are about 87% effective in typical use — meaning roughly 13 in 100 people relying on them as their only method may become pregnant over a year. With perfect use, that drops to about 2 in 100. The NHS gives the same headline figure: condoms are around 98% effective when used correctly every time.
That difference is real-world error: putting the condom on wrong, slippage, breakage, or not using one every single time. Compared with long-acting methods like the IUD, typical-use effectiveness is lower — which is why many people pair condoms with another method (see our methods comparison) for both pregnancy and STI protection.
STI protection: the unique advantage
Condoms are the only contraceptive that also reduces STI risk. The WHO describes correct and consistent condom use as highly effective at reducing transmission of infections spread through bodily fluids, including HIV, gonorrhea, and chlamydia, and credits condom programmes with averting a very large number of HIV infections worldwide.
Protection is partial for infections spread by skin-to-skin contact (such as herpes and HPV), because a condom doesn't cover all exposed skin. They still reduce risk meaningfully — they just aren't a complete shield for those.
Choosing the right condom
Material and fit both matter more than most people expect.
- Latex is the most common material and protects against both pregnancy and STIs.
- Polyurethane and polyisoprene are synthetic alternatives for latex allergy, and the CDC notes these also reduce STI risk.
- Natural membrane ("lambskin") condoms are different. The CDC advises they are not recommended for STI prevention, because the material contains small pores. They can still prevent pregnancy.
- Fit changes failure rates. A condom that is too loose can slip; one that is too tight is more likely to break. Brands vary in width and length, so it is worth trying more than one.
- Check the packet for an expiry date and a recognized safety or quality mark before you use it.
How to use a condom correctly
Most "condom failure" is actually use error. To get close to the ~98% figure:
- Check the expiry date and that the packet isn't damaged.
- Open carefully — no teeth or scissors.
- Put it on before any genital contact, not partway through.
- Pinch the tip to leave space and roll it all the way down.
- Use water- or silicone-based lubricant with latex condoms — oil-based products weaken latex.
- Hold the base when withdrawing, and use a new condom every time and for each act.
- Store away from heat and friction (not long-term in a wallet).
Common mistakes that quietly reduce effectiveness
Beyond the mechanics, a handful of habits explain most of the gap between 98% and 87%:
- Using one "most of the time" rather than every time. Inconsistent use is the single biggest driver of typical-use failure.
- Late application — putting the condom on after contact has already begun.
- Using hand lotion, petroleum jelly, or massage oil as lubricant with a latex condom.
- Storing condoms somewhere hot or abrasive, such as a wallet, for months.
- Doing nothing after a breakage — see the steps below.
Internal (female) condoms
Internal condoms are worn inside the vagina or anus and, like external condoms, offer STI protection as well as pregnancy protection. The NHS reports they are about 95% effective when used correctly, and less effective in typical use.
They have practical advantages: they can be inserted ahead of time, they are not made of latex, and they put control of protection with the person wearing them. They should not be used at the same time as an external condom.
Who condoms suit — and who they don't
Condoms suit people who want protection on demand, with no hormones, no prescription, and no ongoing commitment — including anyone between longer-term methods, or wanting STI protection alongside another contraceptive.
They may be a weaker fit if:
- Preventing pregnancy is a very high priority and a typical-use failure rate of roughly 13 in 100 per year feels too high on its own.
- You cannot rely on consistent use every single time, for any reason.
- You have a latex allergy — in which case switch to polyurethane or polyisoprene rather than abandoning condoms.
If pregnancy prevention is the priority, many people use condoms plus a hormonal or long-acting method. Compare the options in birth control methods compared, or read about non-hormonal birth control if you want to stay hormone-free.
Cost and access
Condoms are among the most accessible contraceptives in the world. They are sold over the counter in pharmacies, supermarkets, and general stores, and the NHS notes that in the UK they are also given out free by contraception clinics, sexual health clinics, and many young people's services. Comparable free or subsidized programmes exist through public health services, university health centres, and community organizations in many countries; elsewhere, cost and availability vary. We don't quote prices, because they differ enormously by country and outlet — check what your local sexual health service provides, as free supplies are more common than people assume.
What to expect when you get them
There is no prescription, no appointment, and usually no ID requirement. In a pharmacy or shop they sit on an open shelf. At a sexual health clinic, staff hand them out routinely and without comment — it is one of the most ordinary things they do all day. Before you buy, glance at the expiry date and the safety mark on the box, and consider picking up more than one size or material until you know what fits well.
If a condom breaks or slips
- Consider emergency contraception. The NHS advises taking it as soon as possible; our guide to the morning-after pill explains the options and time limits.
- Think about STI testing, especially with a new or untested partner. Some infections take time to show on a test, so ask the clinic about timing.
- If HIV exposure is possible, act urgently. The NHS states that post-exposure prophylaxis (PEP) must be started within 72 hours of exposure to have a chance of working.
- A pharmacist or clinician can advise on all of the above quickly, often the same day.
The bottom line
Condoms are a reliable, accessible method that uniquely protects against both pregnancy and STIs — but only when used correctly and every time. Master the basics, choose a material and size that actually fit, avoid the common errors, and consider pairing condoms with a second method if preventing pregnancy is a high priority. To see where condoms sit alongside every other option, start with our contraception guide. This article is general education and is not a substitute for individualized medical advice.
