The four parts of Medicare
Short Answer
The four parts of Medicare are Part A, Part B, Part C, and Part D.
- Part A covers inpatient/hospital coverage.
- Part B covers outpatient/medical coverage.
- Part C covers Part A, Part B, and sometimes Part D prescription drug costs combined into one plan.
- Part D provides prescription drug coverage.
Original Medicare Parts A and B provide important health care coverage but don’t cover everything. That’s why most people choose additional Medicare coverage, Medicare Advantage Plans, or Supplement plans to help fill these gaps.
Frequently asked questions about the four parts of Medicare
How do I choose which parts of Medicare I need?
The parts of Medicare you need depend on your health needs, your budget, and how you want to receive your coverage. Most people start with Original Medicare. This includes Part A (hospital insurance) and Part B (medical insurance). From there, you choose to add standalone Part D prescription plan and possibly a Medigap plan, or you can enroll in a Part C (Medicare Advantage) plan. Part C plans combine your Part A, Part B, and sometimes Part D into one plan.
When can I enroll in Medicare Parts A, B, C, or D?
Most people first enroll during their Initial Enrollment Period, which starts three months before the month you turn 65, includes your birthday month, and ends three months after your birthday month. You can also enroll or make changes to your coverage during the Annual Enrollment period (Oct. 15 – Dec. 7). You may qualify for a Special Enrollment Period if you delayed enrolling because you were still working and had creditable employer coverage or if you have experienced certain life events.
Can I have both Medicare Advantage and Part D?
No. If you are enrolled in a Medicare Advantage plan that includes prescription drug coverage, you cannot enroll in a separate Part D plan. If you join a standalone Part D plan while having a separate Medicare Advantage plan with Part D included, you would typically be disenrolled from the plan and put back on Original Medicare. Medicare Advantage plans often already include Part D, but if your Medicare Advantage plan does not include drug coverage, you may be able to join a separate Part D plan.
Are all four parts of Medicare required?
No. All four parts of Medicare are not required, but you may face late enrollment penalties later if you don’t sign up for certain parts when you are first eligible. Part A is typically automatic when you sign up for Social Security. Part B is voluntary, but you will need it to cover doctor visits and outpatient care. If you don’t sign up for Part B when you’re first eligible, you will pay penalties later unless you have other creditable coverage. Part C (Medicare Advantage) is an alternative to Original Medicare and includes Part A, Part B, and often Part D in one plan. Part D is optional, but you can face late enrollment penalties if you go 63 days without creditable coverage. You must first sign up for Part A and Part B to enroll in a Part C or Part D plan.
