The Three Main Times You Can Enroll in Medicare
Medicare has three separate enrollment windows each year, and missing them can cost you money for the rest of your life. The Initial Enrollment Period is a seven-month window that starts three months before the month you turn 65. The General Enrollment Period runs from January 1 to March 31 each year and is open to anyone, but it carries a permanent penalty if you enroll late. The Special Enrollment Period is a shorter window available only if you meet specific conditions — like losing employer coverage or moving to a new state — and it does not carry a penalty.
Each period has different rules about when coverage starts and what penalties explore. Understanding which period applies to you now prevents you from paying extra for Part B and Part D for years to come.
Key Takeaways
- Your Initial Enrollment Period is seven months long and begins three months before the month you turn 65, giving you time to sign up without penalty.
- If you miss your Initial Enrollment Period, the General Enrollment Period (January 1 to March 31) is always open, but you will pay a permanent 10 percent surcharge on Part B premiums and a 1 percent surcharge on Part D premiums for every 12 months you were late.
- Special Enrollment Periods last 60 or 63 days and explore when you lose employer coverage, move states, or experience other may have access to life changes, and they do not trigger late-enrollment penalties.
- Coverage start dates vary by enrollment period: Initial Enrollment Period coverage begins the first day of your birth month, while General Enrollment Period coverage begins July 1.
- You can enroll through Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.
Your Initial Enrollment Period: The Seven-Month Window
Your Initial Enrollment Period starts three months before the month you turn 65 and ends three months after. If you turn 65 in June, your window opens in March and closes in September. During this period, you can sign up for Medicare Part A (hospital insurance) and Part B (medical insurance) without any penalty, regardless of your health history or current coverage.
Coverage begins on the first day of your birth month if you sign up during the three months before you turn 65. If you wait and sign up during the month you turn 65 or after, coverage starts the first day of the following month. For example, if you turn 65 on June 15 and sign up in July, your coverage begins August 1.
This is the only enrollment period where you avoid penalties entirely. Even if you have employer coverage through a job, signing up during this window protects you from future penalties if that coverage ends.
The General Enrollment Period: January Through March Each Year
The General Enrollment Period runs from January 1 to March 31 every year and is open to anyone who missed their Initial Enrollment Period. You can sign up for Part A and Part B during this window, and coverage begins July 1 of that year. However, this route carries a permanent financial cost.
If you enroll in Part B during the General Enrollment Period instead of your Initial Enrollment Period, Medicare adds a 10 percent surcharge to your Part B premium for as long as you have Medicare. This surcharge applies for every 12 months you were may be able to access but did not enroll. If you were may be able to access for two years and did not sign up, the surcharge is 20 percent. The surcharge never goes away, even if you later drop coverage and re-enroll.
The same rule applies to Part D (prescription drug coverage). A 1 percent surcharge per month of delay gets added to your premium permanently. Because these penalties compound over time, enrolling during the General Enrollment Period should only happen if you truly cannot use your Initial Enrollment Period.
Special Enrollment Periods: Shorter Windows for Life Changes
A Special Enrollment Period is a shorter window — usually 60 or 63 days — that opens when you experience a may have access to event. These periods do not carry late-enrollment penalties, which makes them valuable if you miss your Initial Enrollment Period for a covered reason.
Common may have access to events include losing employer-sponsored health insurance, moving to a new state, getting married or divorced, becoming a U.S. citizen, or having a change in your Medicaid status. Some people also may have access to if they were working past 65 and covered under an employer plan. The exact length and rules of your Special Enrollment Period depend on which event triggered it.
To use a Special Enrollment Period, you must contact Medicare directly and provide proof of the may have access to event — such as a letter from your employer confirming the end of coverage, a divorce decree, or a lease showing you moved. Medicare will not automatically know about these changes, so you have to report them.
Coverage Start Dates by Enrollment Period
| Enrollment Period | When You Sign Up | When Coverage Starts |
|---|---|---|
| Initial Enrollment Period (3 months before to 3 months after age 65) | 3 months before your birth month | First day of your birth month |
| Initial Enrollment Period | Month you turn 65 or later | First day of the following month |
| General Enrollment Period (Jan 1 – Mar 31) | Any time Jan 1 – Mar 31 | July 1 of that year |
| Special Enrollment Period | Within 60–63 days of may have access to event | Varies by event; often the first of the following month |
How to Enroll During Your Enrollment Period
You have three ways to sign up for Medicare: online at Medicare.gov, by phone at 1-800-MEDICARE (1-800-633-4227), or in person at your local Social Security office. The online route is fastest — you can complete the process in 15 to 20 minutes if you have your Social Security number and birth certificate information ready.
When you call or visit in person, a representative will walk you through the same questions and can answer questions about which parts you need. If you have questions about whether you may have access to for a Special Enrollment Period or whether you owe a penalty, calling is often clearer than trying to navigate the website alone.
Have your Social Security number, date of birth, and information about any current health coverage ready before you start. If you are signing up for Part D (prescription drug coverage) at the same time, have a list of your current medications or your pharmacy information available.
Late-Enrollment Penalties and How They Work
A late-enrollment penalty is a permanent increase to your monthly premium that starts if you do not sign up during your Initial Enrollment Period and do not have a may have access to reason for a Special Enrollment Period. The penalty applies only if you enroll during the General Enrollment Period instead.
For Part B, the penalty is 10 percent of the standard premium for every 12 months you were may be able to access but did not enroll. If the standard Part B premium is $165 per month and you were may be able to access for two years without signing up, your penalty is 20 percent, or $33 per month, added to your premium for life. For Part D, the penalty is 1 percent of the national average premium per month of delay.
The only way to avoid this penalty is to sign up during your Initial Enrollment Period or to have a may have access to Special Enrollment Period. If you already owe a penalty, it does not go away if you drop coverage and re-enroll later.
Frequently Asked Questions
What happens if I turn 65 while still working?
If you are still working and covered by your employer's health plan, you can delay signing up for Medicare Part B without penalty. You have a Special Enrollment Period of eight months after you leave your job or your coverage ends, whichever comes first. You must sign up during this window to avoid a late-enrollment penalty. Part A (hospital insurance) does not have the same protection, so you may want to sign up for Part A even if you delay Part B.
Can I change my mind after I sign up?
Yes, but only during specific windows. If you sign up during your Initial Enrollment Period, you can change your coverage choices during the Annual Enrollment Period (October 15 to December 7 each year). If you made a mistake during enrollment, you may be able to request a Special Enrollment Period to correct it, but you must contact Medicare within a short timeframe to explain the error.
Do I have to sign up for Part A and Part B at the same time?
No. You can sign up for Part A without Part B, and vice versa. However, if you delay Part B without a may have access to reason, you will owe a penalty when you eventually enroll. Part A does not have the same penalty structure, so some people sign up for Part A during their Initial Enrollment Period and delay Part B if they still have employer coverage.
What if I miss my Initial Enrollment Period and do not have a Special Enrollment Period?
You can still sign up during the General Enrollment Period (January 1 to March 31), but you will owe a permanent surcharge on your Part B and Part D premiums. The surcharge is 10 percent of Part B for every 12 months you were late, and 1 percent of Part D for every month you were late. These surcharges never go away, so it is important to understand the cost before you enroll.
Can I enroll in Medicare before I turn 65?
Your Initial Enrollment Period does not start until three months before you turn 65. You cannot sign up earlier, even if you want to. The only exception is if you are on Social Security Disability Insurance (SSDI) or have end-stage renal disease, in which case different rules explore — contact Medicare directly to learn about your options.