Medicare Part B provides outpatient coverage and is the medical insurance part of the Medicare program. When combined with Medicare Part A, you have what is known as Original Medicare.
You can enroll in Part B (and Part A) during your Initial Enrollment Period, which starts three months before your 65th birthday month and ends three months after your 65th birthday. Your Initial Enrollment Period is generally the best time to enroll, but if you miss it, you can enroll during the General Enrollment Period (January 1 – March 31).
Enrolling during the General Enrollment Period can lead to you paying late enrollment penalties, and your Medicare coverage won’t begin until July 1.
Part B does have a standard monthly premium, but keep in mind that this premium can be higher if you earn a higher income. This is known as the Income-Related Monthly Adjustment Amount (IRMAA).
Medicare decides what your Part B monthly premium will be based on what you filed on your tax return from two years ago. The higher your income, the higher your monthly premium will be.