Whether you’re actively trying to conceive or wondering if your missed period could mean something more, waiting to find out if you’re pregnant can be a hopeful, anxious or exciting time — and maybe a combination of all three. That’s when you’ll want a reliable, easy-to-decipher pregnancy test Opens a new window.

Found everywhere from drugstores to the internet, pregnancy tests are over-the-counter indicator sticks or test strips that use urine to detect levels of a key pregnancy hormone. Naturally, you'll want to find one that's not only reliable, but also easy to decipher. Here’s everything you need to know about how pregnancy tests work and how to find the best one for you.

How do pregnancy tests work?

Home pregnancy tests all work the same way: by measuring the amount of the pregnancy hormone human chorionic gonadotropin Opens a new window(hCG) in your urine. To take a pregnancy test, you either pee directly on a stick or pee into a cup that you then dip a stick or strip into. Then, after a few nail-biting minutes, you’ll have your results.

Some tests may have different instructions or wait times, so it’s important to follow the directions exactly to make sure you get the most accurate reading. This is especially important when it comes to interpreting the result. For example, you always want to read your results within the window specified in the instructions. "As the paper and urine sample dry, the lines tend to smear and people can think they are pregnant," says Jennifer Roelands, M.D., OB/GYN and the founder of Well Woman MD in Yorba Linda, California.

Types of pregnancy tests

Although home pregnancy tests work the same way, their features can differ. The main types of pregnancy tests include:

• Early pregnancy tests: These pregnancy tests can pick up lower levels of hCG and, in turn, may be able to tell you if you’re pregnant up to five or six days before your missed period. Keep in mind, though, that the closer you are to the date of your expected period, the more accurate a home pregnancy test will be.
• Non-digital pregnancy tests: These pregnancy tests show your results in the form of blue or pink lines. Although they tend to be more affordable, they can also be more difficult to decipher if one of the lines is faint Opens a new window. If that’s the case, wait a day or two to take the test again.
• Digital pregnancy tests: These tests tend to be the easiest to to use and read, since they clearly display your results in words (i.e. “pregnant” or “not pregnant”), leaving little room for error. The downside? Digital tests tend to be more expensive.

Some pregnancy tests are packaged as a stick that you pee on directly, saving you the effort of peeing into a cup, dipping the test into that cup and then cleaning it (although if you prefer this method, many stick tests can also work this way). These can be digital or non-digital. Pregnancy strips, on the other hand, usually need to be dipped into a cup of urine. A third, less common type involves using an eyedropper to take urine from a cup and then drop it into the test’s reservoir.

How accurate are pregnancy tests?

Pregnancy test results are much more accurate if taken once you've missed your period, with most brands estimating about 99 percent accuracy. If you take a test before then, the range might only be around 70 to 75 percent, or even lower in some cases. False positives are rare, but according to Dr. Roelands, some factors that may cause one include testing too early, fertility mediciations that contain hCG or miscarriage. It's also important to note that a chemical pregnancy Opens a new window(which is when an egg implants in the uterine wall but isn't able to develop) or an ectopic pregnancy Opens a new window(when the egg develops outside the uterus) may also lead to positive tests, even if the pregnancy isn't viable. Again, false positives are unusual, but to be absolutely certain, you should schedule an appointment with your OB/GYN following a positive at-home pregnancy test for confirmation.

What to look for when choosing a pregnancy test

Keep these things in mind when you’re shopping for a home pregnancy test:

• Sensitivity: Some tests claim they can detect lower levels of hCG and may be able to tell you if you’re pregnant up to six days before your missed period. Think about when you’ll be taking the test and go from there, again, keeping in mind that the results will be more reliable closer once you’ve missed your period.
• Display: Digital tests that display the results in words are generally more user-friendly than ones with one or two lines, and particularly helpful to people with limited vision, as Dr. Roelands notes. There are also some tests in which the results can be read to you. Clearblue, for example, has partnered with the Be My Eyes app Opens a new windowto offer people with low-vision or who are blind the option to read results privately over a video call, with the help of a Clearblue support specialist.
• Ease of use: Test strip packs are more affordable, but you might prefer the simplicity of a stick test rather than having to dip strips into a cup of urine or transfer urine using a dropper.
• Cost: Home pregnancy tests can range in price Opens a new window, but you'll likely pay more for a digital test or one that claims to be more sensitive. Roeland says this is important to consider if you have unpredictable periods, as you may require multiple tests to get a more accurate result.
• Expiration date: If you are using a pre-purchased pregnancy test, check to make sure the pregnancy test hasn't expired Opens a new window. Otherwise, your results might not be accurate. If you are purchasing tests to use at a later date, make sure the expiration date is far enough away that you have enough time to use them.

When is the best time to take a pregnancy test?

If you've been trying to conceive, you might feel the urge to start testing before you've missed your period, especially if you're tracking your fertility Opens a new windowand seeing promising signals. But Dr. Roelands suggests taking a pause and waiting until you've actually missed your period. If your cycle isn’t regular or you don’t get periods at all, take a test three weeks after possible conception for the most accurate results.

"The accuracy of the test becomes 99 percent once you have passed the day of your missed period,” Dr. Roelands explains. While some tests say they can work as early as 10 days after unprotected sex, the results aren't very reliable and may not be accurate. "It is better to wait so you do not get discouraged about the results," says Dr. Roelands.

You might also be wondering what time of day is best for a pregnancy test. Dr. Roelands suggests right after you wake up, as your urine will be most concentrated at this time and the hCG levels Opens a new windowwill be easiest to detect. You might want to try taking the test before you've had anything to drink, but don't freak out if you forgot and had some water or coffee first. "Consuming a large quantity of water can dilute the sample, but don't stress if you had some water before your test,” says Dr. Roelands. “It is very sensitive to pick up hCG and a glass of water will not ruin the result.”

What if I've missed my period but the pregnancy test is still negative?

If your pregnancy test comes back negative, wait a few days and take another one. "Don't pee on six tests in a row," Dr. Roelands says. If you're still testing negative a few days into your missed period, contact your provider about scheduling a blood test to see if you’re pregnant. "If you haven't had your period by day 35 and the blood test is negative, then it's negative and you didn't ovulate that month," she says.

How we chose the best pregnancy tests

With Dr. Roelands' tips in mind, we scoured through recommendations from the millions of moms in the What to Expect community to find which pregnancy tests worked best for the largest number of people. We also made sure to pay attention to online reviews of each test to read about other users’ experiences.

Here are our picks for the best home pregnancy tests, including digital tests, early detection tests and more.