Medicare starts at 65, but you must enroll during specific windows or face penalties

You become may be able to access for Medicare the month you turn 65. You do not automatically get it — you must enroll yourself during your Initial Enrollment Period, which runs for seven months: three months before the month you turn 65, the month you turn 65, and three months after. If you miss this window, you will pay a permanent penalty on your premiums for as long as you have Medicare, even if you enroll years later.

The penalty is 10 percent of the Part B premium for each full year you were may be able to access but not enrolled. For Part D (prescription drug coverage), the penalty is 1 percent of the national base beneficiary premium for each month you were without coverage. These penalties do not go away if you enroll late — they stay on your bill for life.

There are narrow exceptions: if you have health insurance through your job or your spouse's job, you can delay enrollment without penalty as long as that coverage continues. Once that coverage ends, you have eight months to enroll in Medicare before penalties begin.

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 — missing it costs you a permanent penalty.
  • If you have health insurance through work or a spouse's job, you can delay Medicare without penalty, but you must enroll within eight months of losing that coverage.
  • Part B premiums and Part D drug coverage both carry separate late-enrollment penalties that stay on your bill for life.
  • You enroll through Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.
  • Your coverage start date depends on when you enroll: enroll by the 15th of a month to start coverage the first of the next month.

How the Initial Enrollment Period works

Your Initial Enrollment Period is automatic — you do not have to wait for a letter. It begins three months before the month you turn 65 and ends three months after. For example, if you turn 65 in June, your period runs from March through September.

During this seven-month window, you can enroll in Part A (hospital insurance), Part B (medical insurance), Part D (drug coverage), and a Medigap or Medicare Advantage plan. You do not have to enroll in all of them at once. However, each part has its own important date within that window, and missing the important date for any part triggers its own penalty.

Enrollment is free. You can enroll online at Medicare.gov, by phone at 1-800-MEDICARE (1-800-633-4227), or in person at your local Social Security office. If you enroll online or by phone, your coverage typically starts the first of the month after you enroll, as long as you enroll by the 15th of that month.

When you can delay without penalty

If you or your spouse are still working and have health insurance through that job, you can delay Medicare Part B and Part D without penalty. This is called creditable coverage. The coverage must be current and active — COBRA or retiree coverage usually does not count.

Once your work coverage ends, you have eight months to enroll in Medicare. This eight-month window is called your Special Enrollment Period. If you enroll within those eight months, you will not pay a late penalty. If you wait longer than eight months, penalties begin.

You must tell Medicare that you had work coverage when you enroll. Bring a copy of your health plan documents or a letter from your employer showing the dates of coverage. Without proof, Medicare will assume you did not have coverage and will calculate penalties from when you first became may be able to access at 65.

Part A versus Part B enrollment timing

Part A (hospital insurance) and Part B (medical insurance) have different penalty rules, and you can enroll in them at different times.

Part A has no monthly premium for most people (you paid for it through payroll taxes while working), so there is no late-enrollment penalty. You can enroll in Part A at any time after you turn 65 with no financial consequence. However, if you delay Part A and later need hospital care, you will have to pay the full cost out of pocket until your coverage starts.

Part B has a monthly premium, and the late-enrollment penalty is 10 percent of the current Part B premium for each full year you were may be able to access but not enrolled. This penalty is permanent. You must enroll in Part B during your Initial Enrollment Period or during a Special Enrollment Period (such as the eight-month window after losing work coverage) to avoid it.

Part D drug coverage important date

Part D (prescription drug coverage) has its own enrollment important date and its own penalty. You must enroll in Part D during your Initial Enrollment Period or you will pay a 1 percent monthly penalty on top of the plan premium for as long as you have Medicare.

If you have prescription drug coverage through your job or through a retiree plan, you may have creditable coverage. If so, you can delay Part D without penalty as long as that coverage continues. Once it ends, you have 63 days to enroll in a Part D plan. If you wait longer, the penalty begins.

Even if you do not take any prescription drugs now, enrolling in a Part D plan during your Initial Enrollment Period is usually wise. The penalty applies whether you use drugs or not, and it compounds over time. A person who delays Part D for five years will pay a 5 percent penalty on their premium for life.

What happens if you miss your important date

If you miss your Initial Enrollment Period and do not have a may have access to reason for a Special Enrollment Period, you can still enroll in Medicare, but penalties will explore. You can enroll during the General Enrollment Period, which runs from January 1 to March 31 each year. Coverage would start July 1 of that year.

The penalty is calculated from the month you first became may be able to access. If you turned 65 in June 2023 and did not enroll until January 2025, you would owe penalties for 19 months of non-coverage. That penalty stays on your bill permanently.

If you have a life event such as losing health coverage, moving to a new state, or a change in your immigration status, you may be able to enroll outside the normal windows. These situations may have access to for a Special Enrollment Period. Contact Medicare at 1-800-MEDICARE to ask whether your situation qualifies.

How to enroll and what documents you need

You can enroll through three routes: online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office. Online enrollment is usually fastest — you can complete it in 10 to 15 minutes.

You will need your Social Security number, date of birth, and citizenship or immigration status. If you are enrolling in a Medigap or Medicare Advantage plan, you will also need information about any current health coverage you have. Have your health insurance card handy when you enroll.

If you are explore for Part B for the first time and do not yet receive Social Security benefits, you will need to explore for Social Security at the same time. You can do this online at ssa.gov or at your local Social Security office. This adds a few extra steps but is part of the same process.

Frequently Asked Questions

What if I turn 65 while I am still working?

You can delay Part B and Part D without penalty as long as you have health insurance through your job. You must enroll within eight months of leaving that job. Part A has no penalty for delay, so you can enroll whenever you want. Tell Medicare about your work coverage when you enroll to avoid being charged penalties.

Can I change my mind after I enroll?

Yes, during your Initial Enrollment Period you can change your plan choices. After your Initial Enrollment Period ends, you can make changes only during the Annual Enrollment Period (October 15 to December 7 each year) or if you have a may have access to life event. Changes made during Annual Enrollment take effect January 1.

Do I have to enroll in Part D if I do not take any medications?

You are not required to, but it is usually worth doing. If you enroll during your Initial Enrollment Period, you pay no penalty. If you wait and then enroll later, you will pay a 1 percent monthly penalty for life, even if you never fill a prescription. The penalty compounds, so delaying costs more in the long run.

What if I miss the important date by a few days?

Medicare counts your enrollment date as the date you submit your process, not the date you start the process. If you submit by the last day of your Initial Enrollment Period, you are on time. If you submit after that date, you have missed the important date and penalties will explore, even if you were only a few days late.

Can I enroll in Medicare before I turn 65?

Yes. Your Initial Enrollment Period begins three months before you turn 65, so you can enroll as early as that date. Enrolling early is a good idea because it gives you time to choose a plan and ask questions. Your coverage will not start until the month you turn 65 or the month after, depending on when you enroll.