When You Can Start Medicare: Age Requirements and Enrollment Deadlines

You can start Medicare at age 65, or earlier if you have a disability or end-stage renal disease

Most people become may be able to access for Medicare on the first day of the month they turn 65. You do not have to wait until your birthday itself — if you turn 65 on any day of the month, your coverage can start on the first of that month. If you are already receiving Social Security retirement benefits when you turn 65, Medicare enrollment happens automatically. If you are not yet collecting Social Security, you will need to sign up for Medicare yourself.

You can also start Medicare before age 65 if you have been receiving Social Security Disability Insurance (SSDI) for 24 months, or if you have end-stage renal disease (ESRD) or amyotrophic lateral sclerosis (ALS). These are the only medical conditions that lower the age requirement.

The timing of your enrollment matters. If you miss the window to sign up when you first become may be able to access, you may face a permanent penalty on your premiums. This is why understanding the enrollment periods — and which one applies to you — is important before your 65th birthday arrives.

Key Takeaways

Medicare may be able to access begins at age 65 for most people, or earlier if you receive SSDI for 24 months, have ESRD, or have ALS.
If you are already on Social Security retirement when you turn 65, Medicare enrollment is automatic and requires no action from you.
If you are not yet collecting Social Security, you must sign up for Medicare yourself during your Initial Enrollment Period, which runs for seven months centered on your birth month.
Signing up late can result in a permanent increase to your Part B and Part D premiums, so meeting the enrollment important date is important even if you do not plan to use Medicare right away.
You can delay Part B enrollment without penalty only if you or your spouse still work and have employer health coverage.

What happens if you are already on Social Security

If you are receiving Social Security retirement or survivor benefits when you turn 65, the Social Security Administration will enroll you in Medicare Part A and Part B automatically. You do not need to do anything. Your Medicare card will arrive in the mail about two weeks before your coverage starts.

This automatic enrollment covers both hospital insurance (Part A) and medical insurance (Part B). You will receive a bill for your Part B premium, which is deducted from your Social Security check each month. If you do not want Part B for some reason — for example, because you are still working and have employer coverage — you can decline it, but you must do so in writing within a specific timeframe or the enrollment will stand.

What to do if you are not yet on Social Security

If you are not collecting Social Security when you turn 65, you must sign up for Medicare yourself. You have a seven-month window called your Initial Enrollment Period. It begins three months before the month you turn 65, includes the month of your birthday, and ends three months after.

For example, if you turn 65 in June, your enrollment period runs from March through September. You can sign up online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office. There is no fee to enroll.

If you sign up during the first three months of your Initial Enrollment Period (before your birth month), your coverage will start the month you turn 65. If you sign up in the month of your birthday or after, your coverage will start the following month. This timing matters if you are planning to stop employer coverage on a specific date.

When you can delay Part B without a penalty

You can postpone Part B enrollment past your Initial Enrollment Period without facing a late-enrollment penalty if you or your spouse are still working and have group health insurance through an employer. This is called having "creditable coverage." The employer plan must cover at least 20 employees.

If this applies to you, you have an eight-month window after your employment ends or the employer coverage stops to sign up for Part B without penalty. This is called your Special Enrollment Period. You will need to provide proof of your employer coverage — usually a letter from your employer's benefits department — when you enroll.

Part A (hospital insurance) has no late-enrollment penalty, so you can delay it as long as you want. Part D (prescription drug coverage) and Medigap policies do have penalties for late enrollment, even if you have employer coverage, so those require more careful timing.

What the late-enrollment penalty costs

If you miss your Initial Enrollment Period and do not have creditable coverage, you will pay a permanent increase to your Part B premium. The penalty is 10 percent of the standard Part B premium for each full year you were may be able to access but not enrolled. This penalty stays with you for life, even after you move to a different plan.

For example, if you turn 65 in 2024 but do not enroll until 2026, you owe two years of penalty — 20 percent added to your Part B premium forever. The standard Part B premium changes each year, so your penalty amount will increase along with it.

Part D (prescription drug) has a similar penalty: 1 percent of the national base beneficiary premium for each month you were without coverage. If you go 63 months without Part D coverage, the penalty caps at 63 percent. Unlike Part B, the Part D penalty does not explore if you had other creditable prescription drug coverage during the gap.

Enrolling before you turn 65

You can sign up for Medicare starting three months before your 65th birthday. Many people find it easier to enroll early rather than waiting until their birth month. Signing up in advance gives you time to review your options, ask questions, and make sure your coverage starts smoothly on your may be able to access date.

If you are turning 65 soon and have not yet enrolled, visit Medicare.gov, call 1-800-MEDICARE, or visit your local Social Security office. Have your Social Security number and information about any current health coverage ready. The process takes about 10 minutes online or by phone.

Special cases: Disability and end-stage renal disease

If you have been receiving SSDI for 24 months, you become may be able to access for Medicare automatically at that point — you do not have to wait until 65. Your Medicare enrollment happens without any action from you.

If you have end-stage renal disease (ESRD) or ALS, you can start Medicare right away, regardless of age. You will need to contact Social Security or Medicare directly to enroll, as these do not happen automatically. Call 1-800-MEDICARE or visit your local Social Security office with documentation of your diagnosis.

Frequently Asked Questions

What if I turn 65 in the middle of the month?

Your Medicare coverage will start on the first day of the month you turn 65, not on your actual birthday. If you turn 65 on June 15, your coverage begins June 1. You do not have to wait until June 15 to use your benefits.

Can I sign up for Medicare online?

Yes. Visit Medicare.gov and select "Sign up for Medicare" to enroll online. You can also call 1-800-MEDICARE to enroll by phone, or visit your local Social Security office in person. Online enrollment is usually the fastest option.

Do I have to enroll in Part B if I am still working?

If you have employer health coverage through your job, you can delay Part B without penalty as long as you work there. Once you stop working or lose that coverage, you have eight months to enroll in Part B without penalty. If you miss that window, the late-enrollment penalty applies permanently.

What happens if I enroll late by accident?

Contact Social Security or Medicare right away. If you can show you had creditable coverage (employer insurance or other may have access to coverage) during the gap, you may be able to avoid or reduce the penalty. The sooner you contact them, the better your chances of resolving it.

Can I get Medicare before age 65?

Yes, if you have received SSDI for 24 months, have end-stage renal disease, or have ALS. Otherwise, you must wait until 65. If you are disabled and under 65, contact Social Security to see if you may have access to for SSDI, which would make you may be able to access for Medicare after 24 months of benefits.

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.