Most women should get a mammogram every two years starting at age 40, according to the U.S. Preventive Services Task Force (USPSTF). That said, other major medical organizations recommend yearly mammograms for certain age groups, so the “right” frequency depends on your age, risk factors, and which guidelines your doctor follows.
What the Major Guidelines Recommend
The three organizations you’re most likely to hear about each have slightly different recommendations, which can be confusing. Here’s how they break down:
The USPSTF, which sets the guidelines most insurance plans follow, recommends a mammogram every two years for women aged 40 to 74. This applies to people at average risk of breast cancer, including cisgender women and all people assigned female at birth.
The American Cancer Society (ACS) takes a more age-specific approach. Women 40 to 44 have the option to start yearly screening. Women 45 to 54 should get mammograms every year. At 55 and older, you can switch to every other year or continue annually.
The American College of Radiology (ACR) and Society of Breast Imaging recommend the simplest schedule: annual mammograms starting at age 40 for all average-risk women, continuing as long as you’re in good health.
Your doctor may lean toward any of these depending on your personal health profile. The key takeaway is that no major organization recommends waiting past age 50 to begin screening, and most agree that every two years is the minimum frequency.
Annual vs. Every Two Years: The Trade-Offs
The difference between yearly and biennial screening isn’t just about catching cancer earlier. It also affects how many false alarms you’ll experience along the way. Over a 10-year period starting at age 40, women who screen annually have about a 61% chance of getting at least one false-positive result (being called back for something that turns out to be nothing). For women who screen every two years, that number drops to around 42%. The chance of undergoing a biopsy that finds no cancer is also lower with biennial screening: roughly 5% over a decade compared to 7% with annual screening.
On the other hand, yearly screening catches more cancers at an earlier stage, which is why the ACS recommends it during the years when breast cancer risk is climbing. The USPSTF weighed these trade-offs and concluded that every-other-year screening strikes the best balance between catching cancer and reducing unnecessary procedures for the average-risk population. One reassuring finding: false-positive rates don’t appear to differ based on whether your last mammogram was 12 months ago or 24 months ago. The screening interval itself doesn’t make the test less accurate.
If You’re at Higher Risk
Average-risk guidelines don’t apply to everyone. You may need to start screening earlier or get screened more often if you have a known genetic mutation (like BRCA1 or BRCA2), a strong family history of breast cancer, or a history of chest radiation therapy before age 30. In these cases, doctors often recommend annual mammograms starting before age 40, sometimes supplemented with breast MRI.
Dense breast tissue is another factor that comes up frequently. About half of women have dense breasts, which can make cancers harder to spot on a mammogram. However, dense tissue alone doesn’t automatically mean you need extra screening. The American College of Obstetricians and Gynecologists does not recommend routine supplemental tests like ultrasound or MRI for women with dense breasts who have no other risk factors, noting that current evidence doesn’t show these additional tests improve outcomes in that group. If you have dense breasts plus other risk factors, the conversation with your doctor changes, and additional imaging may be worthwhile.
When to Stop Getting Mammograms
The USPSTF guidelines cover screening through age 74. After that, the evidence becomes less clear-cut, and the decision gets more personal. The core issue is something called overdiagnosis: finding cancers that are real but would never have caused symptoms or shortened your life. For women aged 75 to 84, overdiagnosis rates climb to around 47%. For women with a life expectancy under five years, regardless of age, overdiagnosis exceeds 50%. That means more than half of the cancers detected by screening in this group would never have become a problem, yet the diagnosis can lead to surgery, radiation, or other treatments with real side effects.
This doesn’t mean screening after 74 is never appropriate. A healthy 78-year-old with a life expectancy of 15 or more years faces a different calculation than someone the same age managing multiple serious health conditions. The ACR recommends continuing annual screening for women with a life expectancy of at least five to seven years who are willing to undergo follow-up testing and treatment if something is found. These conversations can feel uncomfortable because they involve thinking honestly about overall health and longevity, but they’re worth having with your doctor.
What Insurance Covers
Under the Affordable Care Act, most health insurance plans are required to cover screening mammograms with no copay, no deductible, and no coinsurance. This applies to non-grandfathered plans, which includes the vast majority of plans created or significantly changed after March 2010. Federal guidelines specify that coverage must include mammograms at least every two years, and as frequently as every year, for average-risk women starting no earlier than 40 and no later than 50.
If you’re called back for additional imaging after a screening mammogram, that follow-up may be classified as diagnostic rather than screening, which can involve cost sharing depending on your plan. Some states have passed laws requiring insurers to cover diagnostic mammograms at the same zero-cost level as screening ones, but this varies. It’s worth checking with your insurance before your appointment if you’ve been called back.
A Practical Schedule to Follow
If you’re at average risk, the simplest approach is to start mammograms at 40 and get one every one to two years. If you want to follow the most conservative path, go annually. If you prefer fewer false positives and are comfortable with the evidence behind biennial screening, every two years is well supported. After 55, the ACS explicitly notes that switching to every other year is reasonable.
Whatever interval you choose, consistency matters more than perfection. A mammogram every two years, done reliably for decades, is far more protective than sporadic yearly screening with gaps. Set a recurring reminder, schedule your next appointment before you leave the imaging center, or tie it to a date you’ll remember, like your birthday month.