Medicare enrollment happens on a schedule, and missing your window can cost you money for life

Medicare is health insurance run by the federal government for people 65 and older. You do not sign up for it automatically when you turn 65 — you have to take action during a specific time period, or you will pay a penalty on your premiums every year you have Medicare. The main enrollment window is the three months before the month you turn 65, the month you turn 65, and the three months after. If you miss this window, you can still enroll, but your monthly premium will be permanently higher.

Your enrollment important date depends on your birth month. If you turn 65 in March, your enrollment window runs from December through June. If you turn 65 in September, it runs from June through December. You can enroll online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.

Key Takeaways

  • Your initial enrollment window is seven months long: three months before you turn 65, the month you turn 65, and three months after.
  • If you enroll after your initial window closes, you will pay a permanent penalty on Part B and Part D premiums for as long as you have Medicare.
  • Medicare has four parts — A (hospital), B (doctor visits), D (prescription drugs), and C (an alternative to A and B) — and you choose which ones you need.
  • If you are still working and covered by your employer's health plan, you may be able to delay enrollment without penalty, but you must tell Medicare about your coverage.
  • You can enroll online at Medicare.gov, by phone, or at your local Social Security office.

Understanding the four parts of Medicare

Part A covers hospital stays, skilled nursing facility care, hospice, and home health services. Most people do not pay a monthly premium for Part A if they or their spouse paid Medicare taxes for at least 10 years while working. Part A has a deductible you pay when you are admitted to the hospital.

Part B covers doctor visits, outpatient care, medical equipment, and preventive services. Part B has a monthly premium that changes each year. In 2024, the standard premium is $164.90 per month, but it varies based on your income. Part B also has a deductible and a 20% coinsurance — you pay 20% of the cost after you meet the deductible.

Part D covers prescription drugs. You choose a Part D plan from private insurance companies, and the premium, deductible, and drugs covered vary by plan. If you do not enroll in Part D when you first become may be able to access and you go without drug coverage, you will pay a penalty when you do enroll.

Part C, also called Medicare Advantage, is an alternative to Parts A and B. It is sold by private insurance companies and usually includes prescription drug coverage. Part C plans often have lower out-of-pocket costs than Original Medicare (Parts A and B), but they limit which doctors and hospitals you can use. You can choose Part C instead of Parts A and B, but you cannot have both.

Your enrollment window and what happens if you miss it

Your Initial Enrollment Period is seven months long. It starts three months before the month you turn 65 and ends three months after. During this window, you can enroll in any Medicare plan without penalty. Coverage can start as early as the first day of the month you turn 65.

If you enroll before the month you turn 65, your coverage will start on the first day of that month. If you enroll during the month you turn 65, coverage starts the first day of the following month. If you enroll after the month you turn 65, coverage starts the first day of the month after you enroll.

If you miss your Initial Enrollment Period, you can still enroll during the General Enrollment Period, which runs January 1 through March 31 each year. Coverage starts July 1. However, you will pay a permanent 10% increase on your Part B premium for each full year you were may be able to access but not enrolled. This penalty stays with you for life. For Part D, the penalty is 1% of the national average premium for each month you were not enrolled, rounded to the nearest dollar.

There is one exception: if you are still working and covered by your employer's health plan, you may have a Special Enrollment Period that lets you delay Medicare without penalty. You must tell Medicare that you have employer coverage when you enroll, or the penalty will explore.

How to enroll online, by phone, or in person

The easiest way to enroll is online at Medicare.gov. Go to the "Sign Up" section and create an account. You will need your Social Security number, date of birth, and information about any current health coverage. You can compare plans, choose the ones you want, and complete your enrollment in one session. You will get a confirmation number when you finish.

You can also call 1-800-MEDICARE (1-800-633-4227) to enroll by phone. A representative will walk you through your options and help you choose plans. The line is open 24 hours a day, seven days a week. If English is not your first language, interpreters are available.

If you prefer to enroll in person, visit your local Social Security office. You can find the nearest office at SSA.gov or by calling 1-800-772-1213. Bring your Social Security card, proof of citizenship or legal residency, and proof of age. Staff can help you understand your options and complete your enrollment.

What to do if you are still working

If you are 65 or older and still working, you can delay enrolling in Medicare Part B without penalty if you are covered by your employer's health plan. However, you must enroll in Part A when you turn 65, even if you are working, because Part A has no penalty for late enrollment.

When you do enroll in Part B, tell Medicare that you have employer coverage. You will need a letter from your employer stating that you are covered under their plan. Without this letter, Medicare will assume you delayed enrollment by choice and will charge you the penalty.

Once you stop working or lose your employer coverage, you have eight months to enroll in Part B without penalty. This is called your Special Enrollment Period. If you miss this window, the standard late-enrollment penalty applies.

Costs you will pay in 2024

Medicare costs vary by plan and by your income. Part A has no monthly premium for most people, but you pay a deductible when you are admitted to the hospital. In 2024, the Part A deductible is $1,632 per benefit period.

Part B has a monthly premium that starts at $164.90 in 2024 if your income is below a certain threshold. If your income is higher, you will pay more. Part B also has a $240 annual deductible in 2024, and you pay 20% of the cost of covered services after you meet the deductible.

Part D premiums vary by plan and range from about $7 to $100 per month, depending on which drugs are covered and which insurance company offers the plan. Part C premiums vary widely and can be $0 to $300 or more per month, depending on the plan and your location.

These amounts change each year. You can see the current costs and compare plans at Medicare.gov.

Frequently Asked Questions

Can I change my Medicare plan after I enroll?

Yes, but only during certain times. The Annual Enrollment Period runs October 15 through December 7 each year, and changes take effect January 1. If you enroll in a Medicare Advantage plan (Part C), you have until December 31 to switch back to Original Medicare (Parts A and B). You can also change your Part D plan during the Annual Enrollment Period.

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 consecutive years to enroll in Medicare. If you meet these requirements, you can enroll the same way as a citizen. Bring proof of your legal status when you enroll.

Do I have to enroll in Part D if I do not take prescription drugs?

You do not have to enroll in Part D right now, but if you go without drug coverage and enroll later, you will pay a penalty. The penalty is 1% of the national average Part D premium for each month you were not enrolled. If you think you might need drugs in the future, it is usually cheaper to enroll now and avoid the penalty.

What happens to my Medicare if I move to another state?

Your Medicare coverage works in all 50 states and U.S. territories. However, if you are in a Medicare Advantage plan, your plan may not be available in your new state. You will have a Special Enrollment Period to switch to a different plan when you move. Contact Medicare.gov or call 1-800-MEDICARE to update your address and see which plans are available in your new location.

Can I enroll in Medicare before I turn 65?

Your enrollment window opens three months before you turn 65, so yes. If your birthday is in March, you can enroll starting in December. Enrolling early gives you time to choose a plan and make sure your coverage starts on time. You cannot enroll more than three months before you turn 65.