When You Can Start Medicare: Age Requirements and Enrollment Windows

The Standard Medicare Age Is 65

You become may be able to access for Medicare at age 65, regardless of your work history or income. This is the baseline rule, and it applies to U.S. citizens and permanent residents who have lived in the country for at least five years.

You do not have to wait until your 65th birthday month to sign up. You can enroll during the three months before you turn 65, the month you turn 65, and the three months after. This seven-month window is called your Initial Enrollment Period. If you miss this window, you will face late-enrollment penalties that increase your premiums permanently.

Turning 65 is not automatic enrollment. You must take the step to sign up yourself, either through Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.

Key Takeaways

You can enroll in Medicare starting three months before you turn 65, and you have until three months after your birthday to sign up without penalty.
If you are still working and have health coverage through your employer, you may be able to delay enrollment without penalty, but you must tell Medicare about your coverage.
Some people under 65 — those with End-Stage Renal Disease, ALS, or who have received Social Security Disability benefits for 24 months — can enroll in Medicare early.
Signing up late costs more: Part B and Part D premiums increase by 10 percent for each year you delay past your Initial Enrollment Period.
You enroll through Medicare.gov, by calling 1-800-MEDICARE, or at your local Social Security office.

Exceptions: Medicare Before Age 65

Three groups of people under 65 can enroll in Medicare. The first is anyone with End-Stage Renal Disease (permanent kidney failure requiring dialysis or transplant). The second is anyone diagnosed with ALS (amyotrophic lateral sclerosis, also called Lou Gehrig's disease). The third is anyone who has been receiving Social Security Disability Insurance (SSDI) for 24 consecutive months.

If you fall into one of these categories, you become may be able to access for Medicare when ready upon meeting the condition, not at 65. You still need to sign up; it does not happen automatically. Contact Social Security or Medicare directly to learn the enrollment process for your situation, since the timing and required documents differ from standard age-65 enrollment.

What Happens If You Work Past 65

Working past 65 does not delay your Medicare may be able to access — you can still enroll at 65. However, if you have health coverage through your current employer, you may be able to delay enrolling in Part B (medical insurance) without penalty. This is called the Special Enrollment Period for people with group health coverage.

To use this exception, your employer coverage must be based on your current work — not coverage you kept after retiring. You must also tell Medicare about your employer coverage when you eventually enroll. If you do not report it, you will be charged late-enrollment penalties even though you had coverage elsewhere.

Part A (hospital insurance) works differently. Most people do not face a penalty for delaying Part A if they have employer coverage, but the rules depend on the size of your employer. Check with Medicare before you decide to delay.

Late Enrollment Penalties and How They Work

If you miss your Initial Enrollment Period and do not have a valid reason (such as active employer coverage), your premiums go up permanently. Part B premiums increase by 10 percent for each full year you delay. If you delay for three years, you pay 30 percent more for the rest of your life on Medicare.

Part D (prescription drug coverage) has a similar penalty: 1 percent of the national base premium for each month you delay. These penalties do not expire — they stay on your bill as long as you are on Medicare.

The only way to avoid these penalties is to enroll during your Initial Enrollment Period, or to have a valid reason for delaying (such as employer coverage or certain life events). Once the penalty is applied, you cannot remove it by enrolling later.

How to Enroll When You Turn 65

Start the process three months before your 65th birthday. You have three main routes: online at Medicare.gov, by phone at 1-800-MEDICARE (1-800-633-4227), or in person at your local Social Security office.

Online enrollment through Medicare.gov is usually the fastest. You will need your Social Security number, proof of citizenship or permanent residency, and information about any current health coverage. The process takes 10 to 15 minutes and you receive confirmation when ready.

If you call, have the same documents ready. A representative will walk you through the questions and enroll you over the phone. If you visit Social Security in person, bring your birth certificate, proof of citizenship, and your Social Security card. Processing takes longer in person, but you leave with a receipt.

Timing: When Coverage Starts After You Enroll

The month your coverage begins depends on when you enroll. If you enroll during your Initial Enrollment Period, coverage typically starts on the first day of the month in which you turn 65, or the first day of the following month if you enroll after the 15th of any month during your window.

If you enroll after your Initial Enrollment Period ends, there is a delay. Coverage does not start until the month after you enroll, and you may face late-enrollment penalties. This is why enrolling early — even if coverage does not start when ready — protects you from penalties.

Medicare and Social Security: Automatic Enrollment

If you are already receiving Social Security retirement benefits when you turn 65, you are automatically enrolled in Medicare Part A and Part B. You do not have to do anything. Medicare will send you a card in the mail about two months before your 65th birthday.

If you are not yet receiving Social Security, you must enroll in Medicare yourself. Even if you plan to delay Social Security to increase your benefit amount, you should still enroll in Medicare at 65 to avoid penalties.

Automatic enrollment does not include Part D (prescription drug coverage). You must sign up for Part D separately during your Initial Enrollment Period if you want it, or you will face a late-enrollment penalty if you add it later.

Frequently Asked Questions

Can I enroll in Medicare before I turn 65 if I am still working?

No, unless you have End-Stage Renal Disease, ALS, or have been on Social Security Disability for 24 months. If you are working and have employer coverage, you can delay enrolling in Part B without penalty, but you must still enroll at 65 and report your employer coverage to Medicare.

What happens if I miss my Initial Enrollment Period?

You can still enroll, but you will pay higher premiums for the rest of your life. Part B premiums increase 10 percent for each year you delay. You can enroll during the General Enrollment Period (January 1 to March 31 each year), with coverage starting July 1.

Do I have to enroll in all four parts of Medicare at 65?

No. Part A (hospital) and Part B (medical) are the main coverage. Part D (drugs) is separate and optional, but delaying it costs more later. Part C (Medicare Advantage) is an alternative to Part A and B, not an addition.

If I am still working at 65, do I have to enroll in Medicare?

You should enroll in Part A at 65 even if you are working, because there is usually no penalty for delaying it. For Part B, if you have employer coverage, you can delay without penalty — but you must tell Medicare about your coverage when you eventually enroll.

What if I become a U.S. citizen after 65?

You become may be able to access for Medicare at 65 if you are a citizen or permanent resident who has lived in the U.S. for at least five years. If you become a citizen after 65, you have a Special Enrollment Period to sign up without penalty.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.