Medicare Part A and Part B together make up Original Medicare, the foundation of the U.S. government’s health insurance program for people aged 65 and older, as well as certain younger individuals with disabilities or specific medical conditions. These two parts are designed to cover most essential healthcare needs by separating coverage into hospital-based services (Part A) and medical and outpatient services (Part B). This structure helps beneficiaries understand what type of care is covered and how costs are shared between the individual and Medicare.
Medicare Part A is often called hospital insurance because it covers care that typically requires formal admission to a medical facility. This includes inpatient hospital stays, limited stays in skilled nursing facilities following a hospital admission, hospice care for terminally ill patients, and some home health services. Most beneficiaries do not pay a monthly premium for Part A if they have paid Medicare payroll taxes during their working years. However, Part A is not completely free—there are deductibles and limits on how long Medicare will pay for certain types of care, especially for extended hospital or nursing facility stays.
Medicare Part B is known as medical insurance and focuses on everyday and preventive healthcare. It covers doctor visits, outpatient hospital services, preventive screenings, lab tests, mental health services, ambulance transportation, and durable medical equipment such as wheelchairs or oxygen supplies. Unlike Part A, Part B requires a monthly premium, and beneficiaries must also meet an annual deductible. After that, Medicare generally pays about 80% of the approved cost for covered services, leaving the remaining 20% as the patient’s responsibility.
A key strength of Medicare Part A and B is their emphasis on access and prevention. Part B, in particular, encourages early detection of illnesses by covering preventive services such as cancer screenings, cardiovascular checks, and vaccinations. This approach helps reduce long-term healthcare costs and improves overall health outcomes. At the same time, Part A ensures that beneficiaries are protected against the high costs of hospital stays and serious medical events.
Despite their broad coverage, Original Medicare has gaps. It does not include routine dental, vision, or hearing care, and it does not cap annual out-of-pocket expenses. Because of these limitations, many beneficiaries choose to add Medigap (Medicare Supplement) plans, Medicare Part D (prescription drug coverage), or switch to a Medicare Advantage (Part C) plan to gain additional benefits and financial protection.
