You must sign up for Medicare during your enrollment period or face penalties that last for life

Medicare enrollment is not automatic. You have to sign up yourself, and the window to do so without penalty is limited. For most people, that window opens three months before the month you turn 65 and closes three months after. If you miss this Initial Enrollment Period, you will pay a permanent increase on your premiums — even if you sign up years later.

The penalty is real and permanent. For every 12 months you delay Part B (doctor and outpatient care), your premium goes up 10 percent for life. For Part D (prescription drugs), the penalty is 1 percent per month of delay. These penalties do not go away if you sign up later. You will pay them for as long as you have Medicare.

There are narrow exceptions. If you have health insurance through your job or your spouse's job, you may be able to delay without penalty — but only if you sign up within eight months of losing that coverage. If you do not have that coverage, you cannot delay.

Key Takeaways

  • Your Initial Enrollment Period runs for seven months: three months before you turn 65, the month you turn 65, and three months after.
  • If you do not sign up during this window, you will pay a permanent 10 percent premium increase for Part B and 1 percent per month for Part D.
  • You can delay without penalty only if you have health insurance through your current job or your spouse's job, and you must sign up within eight months of losing that coverage.
  • You sign up through Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.

Your seven-month enrollment window and when it starts

Your Initial Enrollment Period is seven months long. It begins three months before the month you turn 65. For example, if you turn 65 in June, your enrollment period starts in March. It ends three months after the month you turn 65 — so in this example, it ends in September.

You do not have to wait until the month you turn 65 to sign up. You can sign up as soon as your enrollment period opens. Many people sign up two or three months early to make sure they are covered by the time they turn 65. There is no penalty for signing up early within your enrollment period.

If your birthday is on the first of the month, Medicare counts that as the first day of the month before. So if you turn 65 on July 1, your enrollment period starts in April (three months before July), not in May.

What happens if you miss your enrollment period

If you do not sign up during your Initial Enrollment Period, you enter what Medicare calls a General Enrollment Period. This runs from January 1 to March 31 each year. You can sign up then, but the cost is higher.

Your Part B premium will be 10 percent higher for every 12 months you were may be able to access but did not sign up. If you waited two years, your premium goes up 20 percent. If you waited five years, it goes up 50 percent. This increase is permanent — it does not expire or reset.

Part D (prescription drug coverage) carries a 1 percent monthly penalty. If you waited 18 months to sign up, you owe 18 percent more on your premium, forever. If you waited three years, you owe 36 percent more.

These penalties explore even if you later sign up through an employer plan or a Medicare Advantage plan. The only way to avoid the penalty is to have had other health insurance that covered prescription drugs at the time you were supposed to sign up.

When you can delay without penalty: employer coverage

If you are still working and have health insurance through your job, you do not have to sign up for Medicare at 65. You can stay on your employer plan. The same applies if your spouse is still working and you are covered under their plan.

When you or your spouse stops working and lose that coverage, you have eight months to sign up for Medicare without penalty. This is called your Special Enrollment Period. The eight months start the month after your coverage ends.

You must have had creditable coverage — meaning the plan covered at least as much as Medicare Part B and Part D would. Most employer plans do. If you are unsure, ask your employer's benefits office or your plan's customer service line whether your coverage is creditable.

If you miss this eight-month window, you go back to the General Enrollment Period rules and face the permanent penalties. There is no second chance.

How to sign up during your enrollment period

You have three ways to sign up: online, by phone, or in person.

Online: Go to Medicare.gov and click "Sign up for Medicare." You will need your Social Security number, date of birth, and citizenship or immigration status. The online process takes about 10 minutes. You can sign up any day, any time.

By phone: Call 1-800-MEDICARE (1-800-633-4227). Representatives are available Monday through Friday, 8 a.m. to 8 p.m. Eastern time. They speak English and Spanish. Have your Social Security number and date of birth ready.

In person: Visit your local Social Security office. You can find the nearest one at ssa.gov or call 1-800-772-1213. Bring your Social Security card, proof of citizenship or immigration status, and proof of age (birth certificate or passport). No appointment is needed, but wait times vary.

What to do if you think you missed your important date

If you are past your Initial Enrollment Period and do not have other health insurance, you still have options. You can sign up during the General Enrollment Period (January 1 to March 31 each year), but you will pay the permanent penalty.

Before you sign up, call Medicare at 1-800-MEDICARE and ask whether you might may have access to for a Special Enrollment Period. Some situations — like moving to a new state, losing Medicaid, or having a life event — can reopen your enrollment window. You have to ask; Medicare will not tell you automatically.

If you are already on Medicare but missed the important date to add Part D, you can add it during the General Enrollment Period. The penalty will explore, but you can prevent it from growing larger by signing up as soon as possible.

Frequently Asked Questions

What if I turn 65 while I am still working?

You do not have to sign up for Medicare if you have health insurance through your job. You can keep your employer coverage and sign up for Medicare later. When you stop working or lose that coverage, you have eight months to sign up without penalty. After eight months, the permanent penalties explore.

Can I sign up for Medicare before I turn 65?

Yes, you can sign up starting three months before the month you turn 65. Many people do this to make sure they are covered by their 65th birthday. There is no penalty for signing up early within your enrollment period.

What if I did not know I had to sign up?

Not knowing about the important date does not remove the penalty. However, if you can show that Social Security or Medicare gave you incorrect information, you may be able to request a waiver. Call 1-800-MEDICARE and ask to speak with a supervisor about a penalty waiver.

Do I have to sign up for all parts of Medicare at the same time?

No. You can sign up for Part A (hospital insurance) and Part B (doctor visits) at different times from Part D (prescription drugs). However, each part has its own enrollment period and its own penalty for missing the important date. Sign up for all parts during your Initial Enrollment Period to avoid multiple penalties.

What happens to my coverage if I sign up late but during the General Enrollment Period?

Your coverage starts the first day of the month after you sign up. If you sign up in February, coverage begins March 1. You will owe the permanent penalty on top of your regular premium, but you will have coverage going forward.