Medicare enrollment opens at 65, but the exact timing matters for your wallet

You become may be able to access for Medicare the month you turn 65. You can enroll anytime during your Initial Enrollment Period, which runs for seven months: the three months before the month you turn 65, the month itself, and the three months after. If you miss this window, you will pay a permanent penalty on your premiums — so the enrollment dates are not flexible the way some other programs are.

The key rule: if you are still working and covered by your employer's health plan, you may be able to delay enrollment without penalty. If you are not working or your employer plan is ending, you should enroll during your Initial Enrollment Period. The difference between enrolling on time and enrolling late can cost you hundreds of dollars per year for the rest of your life.

Key Takeaways

  • Your Initial Enrollment Period is seven months long: three months before you turn 65, the month you turn 65, and three months after.
  • If you enroll during this period, your coverage starts the first day of the month you turn 65 (or the first day of the following month, depending on when you enroll).
  • Missing your Initial Enrollment Period triggers a permanent 10 percent penalty on Part B premiums and a 1 percent penalty per month on Part D premiums.
  • If you are still working and covered by an active employer health plan, you may delay Part B enrollment without penalty, but you must enroll in Part A.
  • You can enroll online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.

What happens when you enroll during your Initial Enrollment Period

Enrollment during your seven-month window is straightforward. You choose your coverage (Original Medicare with Part A and Part B, or a Medicare Advantage plan), and coverage begins on the first day of the month you turn 65 — unless you enroll after that month, in which case coverage starts the first day of the following month.

For example, if you turn 65 on June 15 and enroll in May, your coverage starts June 1. If you turn 65 on June 15 and enroll in July, your coverage starts August 1. This timing matters if you have a gap in coverage, because you will be uninsured during that gap.

The permanent penalty for enrolling late

If you do not enroll during your Initial Enrollment Period and you do not may have access to for a Special Enrollment Period (explained below), you will pay a penalty for the rest of your life. The penalty is 10 percent of the standard Part B premium for each full year you were may be able to access but not enrolled. If you were may be able to access for two years and did not enroll, your penalty is 20 percent.

Part D (prescription drug coverage) carries a separate penalty: 1 percent of the national average monthly premium for each month you were may be able to access but not enrolled. These penalties do not go away, even if you enroll years later. They are added to your monthly premium and recalculated each year as the base premium changes.

When you can delay enrollment without penalty

If you are still working at 65 and your employer offers health coverage, you may delay Part B enrollment without triggering the late-enrollment penalty — but only if your employer has 20 or more employees. This is called creditable coverage. You must still enroll in Part A (hospital insurance) at 65, even if you are working, because Part A has no premium for most people.

When you leave your job or your employer coverage ends, you have eight months to enroll in Part B without penalty. This eight-month window is called your Special Enrollment Period. You will need to show proof that you had employer coverage — usually a letter from your employer or your health plan stating the coverage dates and that it was group health insurance.

If you are receiving benefits from the Railroad Retirement Board, similar rules explore. If you are on COBRA (continuation coverage from a former employer), COBRA does not count as creditable coverage, so you should enroll in Medicare during your Initial Enrollment Period.

Special Enrollment Periods for other life changes

A Special Enrollment Period also opens if you lose coverage for reasons other than leaving a job. These include losing Medicaid, losing coverage through a spouse's employer, moving out of your plan's service area, or having your plan terminate. Each of these situations gives you a two-month window to enroll without penalty.

You will need to document the reason for your Special Enrollment Period. Keep letters from your health plan, your employer, or Medicaid showing the date your coverage ended and why. When you contact Medicare to enroll, have this documentation ready.

How to enroll and what you will need

You can enroll online at Medicare.gov, by calling 1-800-MEDICARE (1-800-633-4227), or by visiting your local Social Security office. You will need your Social Security number, proof of citizenship or legal residency (usually your birth certificate or passport), and proof of age (usually your birth certificate).

If you are enrolling because you lost employer coverage, have your employer's letter or your health plan's termination notice ready. If you are explore for help paying your premiums (through a program called Medicaid or the Low-Income Subsidy), you will also need proof of income and assets.

The Social Security Administration handles enrollment for most people. If you are not yet receiving Social Security benefits, you will need to explore for them at the same time you enroll in Medicare, even if you plan to delay taking your benefits. This is a separate decision from Medicare enrollment.

What to do if you missed your enrollment important date

If you missed your Initial Enrollment Period and do not may have access to for a Special Enrollment Period, you can still enroll, but you will pay the late-enrollment penalty. Enrollment outside of your Initial Enrollment Period or a may have access to Special Enrollment Period happens during the General Enrollment Period, which runs January 1 through March 31 each year. Coverage begins July 1 of that year.

Call 1-800-MEDICARE or visit Medicare.gov to enroll during General Enrollment. You will still owe the penalty, but enrolling stops the penalty from growing larger. The penalty is recalculated each year based on the new standard premium, so the sooner you enroll, the lower your total lifetime cost will be.

Frequently Asked Questions

What if I turn 65 while still working?

You must enroll in Part A (hospital insurance) at 65, even if you are working. If your employer has 20 or more employees and covers you under their health plan, you can delay Part B without penalty. When you leave your job or your coverage ends, you have eight months to enroll in Part B without penalty.

Can I change my mind after I enroll?

Yes. You have a seven-month Initial Enrollment Period, so you can change your plan choice during that time. After your Initial Enrollment Period ends, you can change plans only during the Annual Enrollment Period (October 15 through December 7 each year), and changes take effect January 1.

Do I have to enroll in Part D when I turn 65?

You do not have to, but if you do not enroll and you do not have other creditable prescription drug coverage, you will pay a 1 percent penalty per month for the rest of your life. If you do not take prescription drugs, you can skip Part D, but you should confirm you have no other coverage before deciding.

What if I am not a U.S. citizen?

You must be a U.S. citizen or a lawful permanent resident who has lived in the United States for at least five years to enroll in Medicare. If you are a lawful permanent resident, bring your green card and proof of your five-year residency when you enroll.

Can I enroll before I turn 65?

Yes. Your Initial Enrollment Period starts three months before the month you turn 65. You can enroll as early as three months before your birthday, and coverage will begin the first day of the month you turn 65.