When You Can Start Medicare: Age Requirements and Your Options

You can begin Medicare at age 65, but the exact month depends on when you were born and whether you have already started Social Security

Medicare may be able to access starts the first day of the month you turn 65. If you were born on the first of any month, your coverage begins that month. If you were born on any other day, your coverage begins the first day of the following month. You do not have to wait until your birthday to sign up — in fact, you should sign up during the three months before you turn 65 to avoid a late enrollment penalty.

If you have already started receiving Social Security before age 65, Medicare will begin automatically the month you turn 65. You will receive your Medicare card in the mail about two weeks before your coverage starts. If you have not yet claimed Social Security, you will need to sign up for Medicare separately through Social Security, Medicare.gov, or your local Social Security office.

Key Takeaways

Medicare begins the first day of the month you turn 65, regardless of the exact date within that month you were born.
You should sign up during the three months before you turn 65 to avoid paying a penalty for late enrollment.
If you are already receiving Social Security, Medicare will start automatically when you reach 65.
You can sign up through Medicare.gov, by calling Social Security at 1-800-772-1213, or in person at your local Social Security office.
If you are still working and have employer health insurance, you may be able to delay Medicare without penalty under certain conditions.

When to sign up: the three-month window

Your Initial Enrollment Period is seven months long: the three months before you turn 65, the month you turn 65, and the three months after. You should sign up during the first three months — before your birthday — so your coverage starts on time and you avoid a late enrollment penalty.

If you miss this window and sign up after the month you turn 65, you will pay a permanent penalty on your Part B premium (the part that covers doctor visits and outpatient care). The penalty is 10 percent of the standard Part B premium for each full year you were may be able to access but did not sign up. That penalty stays with you for life, even if you switch plans later.

The same penalty applies to Part D (prescription drug coverage) if you go without it for more than 63 days in a row. If you have had creditable drug coverage through an employer or union, you may not owe this penalty, but you will need to prove it when you sign up.

If you are still working at 65

You can delay Medicare without penalty if you are still working and covered by your employer's health plan. This is called the Special Enrollment Period for people with group health plan coverage. You must meet two conditions: your employer must have at least 20 employees, and you must be actively employed (not retired).

If both conditions are true, you can wait to sign up for Medicare until you actually retire or lose your employer coverage, whichever comes first. When that happens, you have eight months to sign up without owing a late enrollment penalty. This can save you money if your employer plan is comprehensive and you do not need Medicare yet.

If your employer has fewer than 20 employees, Medicare becomes your primary insurance at 65 even if you are still working. Your employer plan becomes secondary. You should still sign up for Medicare during your Initial Enrollment Period to avoid penalties.

How to sign up before age 65

You have three ways to sign up: online at Medicare.gov, by phone, or in person. The online route is fastest. Go to Medicare.gov, click "Sign up for Medicare," and follow the steps. You will need your Social Security number, date of birth, and information about any current health coverage. The process takes about 10 minutes.

By phone, call Social Security at 1-800-772-1213. Representatives are available Monday through Friday, 7 a.m. to 7 p.m. Eastern time. Have your Social Security number and information about your current coverage ready. Wait times are often shorter early in the week and early in the day.

In person, visit your local Social Security office. You can find the nearest one at ssa.gov/locator. Bring your Social Security card, birth certificate, and proof of citizenship (passport, naturalization papers, or birth certificate). If you have employer coverage, bring that information too.

What happens after you sign up

After you sign up, Social Security will mail you a Medicare card within two weeks. Your coverage will start on the first day of the month you turn 65 (or the first day of the following month if you were born after the first of the month). You do not need to do anything else — the card will arrive automatically.

When your card arrives, check it for errors. Your name, date of birth, and Medicare number should all be correct. If anything is wrong, call Medicare at 1-800-MEDICARE (1-800-633-4227) to request a corrected card.

You will also receive information about your coverage options. Medicare has two main paths: Original Medicare (Part A and Part B) plus a separate Part D plan for drugs, or a Medicare Advantage plan (Part C) that bundles hospital, doctor, and drug coverage into one plan. You do not have to choose right away — your coverage will default to Original Medicare if you do not make a choice, but you can switch during the Annual Enrollment Period (October 15 to December 7 each year).

Late enrollment penalties and how to avoid them

A late enrollment penalty on Part B stays on your premium for as long as you have Medicare. If the standard Part B premium is $165 per month and you were one year late signing up, you would pay an extra $16.50 per month for life — that adds up to $198 per year. Over 10 years of retirement, that is nearly $2,000 in extra costs.

The Part D penalty works the same way. If you go without drug coverage for more than 63 days after you first become may be able to access, you pay 1 percent of the national average Part D premium for each month you were without it. That penalty also stays with you permanently.

The only way to avoid these penalties is to sign up during your Initial Enrollment Period or to have a may have access to reason for delay (like active employer coverage). Once the penalty is applied, you cannot have it removed, even if you move to a different state or switch plans.

Special situations: disability, ESRD, and ALS

You can begin Medicare before age 65 if you have been receiving Social Security Disability Insurance (SSDI) for 24 months, if you have End-Stage Renal Disease (ESRD), or if you have been diagnosed with ALS (amyotrophic lateral sclerosis). These are the only medical conditions that lower the age requirement.

If you receive SSDI, Medicare will start automatically 24 months after your disability benefits began. You do not need to sign up separately. If you have ESRD, you can sign up as soon as you are diagnosed, and coverage will begin the first day of the month you sign up (or the following month, depending on when you were born). If you have ALS, Medicare begins the first month you receive SSDI, with no 24-month waiting period.

Frequently Asked Questions

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

Your Medicare coverage will begin on the first day of the following month. For example, if you turn 65 on March 15, your coverage starts April 1. You should still sign up during the three months before your 65th birthday to may support your card arrives on time.

Can I delay Medicare past 65 if I do not want it yet?

You can delay without penalty only if you have active employer coverage through a company with at least 20 employees and you are still working. Otherwise, you should sign up during your Initial Enrollment Period to avoid a permanent penalty on your premiums, even if you do not use Medicare right away.

Do I have to sign up for Part B, or can I just take Part A?

Part A (hospital insurance) is automatic if you are receiving Social Security. Part B (doctor and outpatient care) is optional, but if you do not sign up during your Initial Enrollment Period, you will pay a 10 percent penalty on the Part B premium for each year you were may be able to access but did not enroll.

What if I miss my Initial Enrollment Period?

You can still sign up after your Initial Enrollment Period ends, but you will owe a late enrollment penalty on Part B and Part D that lasts for the rest of your life. The penalty is permanent and cannot be removed. Sign up as soon as you realize you missed the important date to stop the penalty from growing.

Will my employer insurance stop when I turn 65?

Not automatically. If you are still working and your employer has at least 20 employees, your employer plan can remain primary and Medicare becomes secondary. Check with your employer's benefits office about what happens to your coverage when you reach 65.

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.