Medicare is a U.S. government health insurance program that covers people age 65 or older, but can also cover younger individuals with certain types of illnesses or medical conditions. Medicare covers defined health care services. Some services covered by Medicare require Medicare enrollees to share the costs. Some don't.

If you're eligible to receive Social Security benefits when you turn 65, you will automatically be enrolled in Medicare Part A, which covers hospital costs, and Medicare Part B, which covers visits to the doctor. Enrollment requires no action from you. However, you must enroll for other parts of the Medicare program, such as Medicare Part D (drug coverage) or Medicare Supplement insurance (Medigap). If you miss your initial enrollment period or want to change plans later, there are several annual Medicare open enrollment periods.

Four types of Medicare programs are available to individuals. Basic Medicare typically includes Parts A and B or the Medicare Part C plan. Individuals also may opt to enroll in Medicare Part D for prescription drug coverage.

Medicare Part A covers hospital, skilled nursing facility, hospice, and some home-based healthcare costs. However, this plan doesn't cover long-term, assisted living, or custodial care facilities. Coverage is automatic for anyone who receives Social Security benefits.

Medicare Part B covers costs for outpatient care, such as doctor visits. Part B also covers preventive services, ambulance transport, certain medical equipment, and mental health care. The standard monthly premium for Medicare Part B enrollees is $185 for 2025. The annual deductible is $257 in 2025.

However, premiums are higher for taxpayers with modified adjusted gross income (MAGI) above limits adjusted annually.

Individuals eligible for Medicare Parts A and B are also eligible for Part C, also known as Medicare Advantage. You purchase Medicare Advantage plans from private insurers or an agent rather than Medicare. These plans must offer coverage that is at least equivalent to Original Medicare (Parts A and B).

Many Medicare Advantage plans offer annual caps on out-of-pocket costs and provide benefits such as dental, vision, and hearing care.

Medicare Advantage (Part C) comes with some disadvantages, including preauthorization requirements and less flexibility in choosing doctors.

Medicare offers supplemental prescription drug coverage through Medicare Part D. Enrollees in Medicare Part A or Part B may enroll in Part D to receive subsidies for prescription drug costs that Original Medicare plans do not cover.

Both Medicare and Medicaid are government-sponsored health insurance programs, but there are different eligibility requirements for each program.

While Medicare is intended for those ages 65 and older and younger people with certain health conditions, Medicaid is a joint federal and state program that provides health care coverage to low-income adults and children. To qualify for Medicaid, you must meet income requirements. Anyone with Medicaid coverage is eligible to receive services such as doctor and nursing care, X-rays, hospitalization, home health care, and lab and X-ray services. Some states may offer expanded coverage for prescriptions, physical therapy, dental services, and medical transportation.

Medicare doesn't cover the cost of some important health care services. It doesn't pay for long-term care, also known as custodial care. U.S. Centers for Medicare and Medicaid Services. "Nursing Home Care." Medicaid, however, the joint state and federal health program for low-income people, may pay custodial costs.

Other common expenses that Medicare does not cover include:

• Eye exams and eyeglasses
• Dentures
• Most dental care
• Medical care overseas
• Cosmetic surgery
• Massage therapy

For individuals with qualifying work history, there's no premium for Medicare Part A. The standard monthly premium for Medicare Part B is $185 for 2025. The premium is automatically deducted from Social Security checks.