When You Can Start Medicare: Age Requirements and Timing

The Standard Age for Medicare Is 65

You become may be able to access for Medicare at age 65, regardless of whether you are still working. This is the baseline rule, and it applies to nearly everyone — U.S. citizens and permanent residents who have lived in the country for at least five years.

You do not have to retire to sign up. You do not have to stop working. You do not have to be poor. Age 65 is the threshold, and it stands on its own.

The enrollment window opens three months before the month you turn 65 and closes three months after. If you miss this window, you may face a permanent penalty on your premiums — typically 10 percent per year of delay, for as long as you have Medicare Part B.

Key Takeaways

Medicare begins at age 65 for most people, and you can sign up starting three months before your birthday.
If you are still working and have employer health insurance, you may be able to delay Part B without penalty if your employer has 20 or more employees.
Some people with disabilities or end-stage renal disease can start Medicare before 65, but the process and timing differ.
Missing your enrollment window can add a permanent 10 percent penalty to your Part B premium for each year you delay.
You sign up through Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.

When You Can Start Before Age 65

Three groups of people can start Medicare before turning 65: those receiving Social Security Disability Insurance (SSDI) for at least 24 months, those with end-stage renal disease (ESRD) requiring dialysis or a transplant, and those with amyotrophic lateral sclerosis (ALS).

If you receive SSDI, Medicare begins automatically after you have been on disability for 24 months. You do not need to do anything — the Social Security Administration will enroll you. The 24 months is measured from the date your disability benefits started, not from when you first applied.

If you have ESRD, you can start Medicare the first day of the month in which your dialysis treatment begins, or the first day of the month you receive a kidney transplant — whichever comes first. You must sign up yourself; it does not happen automatically. If you have ALS, Medicare begins the first month you are approved for SSDI, with no 24-month waiting period.

How the Enrollment Window Works

Your Initial Enrollment Period lasts seven months total: three months before the month you turn 65, the month you turn 65, and three months after. During this window, you can sign up for Part A (hospital insurance) and Part B (medical insurance) without penalty.

If you sign up before the month you turn 65, your coverage typically starts the first day of the month you turn 65. If you sign up during the month you turn 65, coverage starts the first day of the following month. If you sign up after the month you turn 65, there is a delay — coverage starts the first day of the month after you sign up.

This timing matters if you have a gap in health insurance. If you wait until after your birthday to sign up, you may have weeks or months with no coverage.

Delaying Part B If You Have Employer Coverage

If you or your spouse are still working and covered by an employer health plan with 20 or more employees, you can delay Part B without penalty. This is called creditable coverage, and it protects you from the late-enrollment penalty.

To use this exception, you must sign up for Part A at 65 (to protect your hospital coverage), but you can wait to sign up for Part B until you or your spouse leave the job or lose the employer coverage. When you do sign up for Part B, you have an eight-month window from the date the coverage ends.

You must tell Medicare that you have employer coverage when you sign up for Part A. Bring a copy of your insurance card or a letter from your employer stating the number of employees and confirming that the plan is active. Without this documentation, Medicare will assume you should have signed up for Part B and may explore the penalty retroactively.

What Happens If You Miss Your Enrollment Window

If you do not sign up for Part B during your Initial Enrollment Period and you do not have creditable coverage, you will pay a permanent penalty. 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.

For example, if you turn 65 in January 2024 and do not sign up until January 2026, you have delayed two years. Your penalty would be 20 percent of the current Part B premium, added to your monthly bill for as long as you have Medicare.

You can sign up for Part B during the General Enrollment Period, which runs January 1 through March 31 each year. Coverage begins July 1 of that year. But the penalty applies unless you have a may have access to exception, such as creditable employer coverage or a Special Enrollment Period triggered by a life event.

How to Sign Up for Medicare

You have three ways to sign up: online at Medicare.gov, by phone at 1-800-MEDICARE (1-800-633-4227), or in person at your local Social Security office.

Online is fastest. Go to Medicare.gov, create an account, and follow the process. You will need your Social Security number, date of birth, and citizenship or permanent resident status. If you are signing up for Part B and have employer coverage, have your insurance card or employer letter ready.

By phone, a representative will walk you through the same questions. The wait time varies, but calling early in the week and early in the day usually means a shorter hold. In person, bring the same documents plus a photo ID and proof of residency (a utility bill or lease works).

Sign up at least one month before your coverage should start. If you are turning 65 next month, do not wait — enroll now.

Special Situations: Government Employees and Railroad Workers

If you worked for the federal government and are covered by the Federal Employees Health Benefits Program (FEHB), the rules are the same: you can delay Part B without penalty while you have FEHB coverage. When you retire or lose FEHB, you have eight months to sign up for Part B.

Railroad workers covered by the Railroad Retirement Board (RRB) follow similar rules. You can delay Part B while you have RRB coverage, and you have eight months after coverage ends to sign up without penalty.

In both cases, you must still sign up for Part A at 65. Part A is hospital insurance and is separate from your employer or RRB plan. Delaying Part A can also trigger a penalty, though the rules are slightly different — the penalty applies only if you delay after you are no longer covered by an employer plan.

Frequently Asked Questions

Can I sign up for Medicare before I turn 65?

You can sign up three months before your 65th birthday. If you are on SSDI and have been receiving it for 24 months, Medicare starts automatically. If you have ESRD or ALS, you can sign up as soon as you meet the medical criteria, which may be before 65.

What if I am still working at 65 and do not want Medicare?

If you have employer coverage with 20 or more employees, you can delay Part B. You must still sign up for Part A to avoid a penalty. Once you leave your job or lose coverage, you have eight months to sign up for Part B without a late penalty.

Do I lose Medicare if I go back to work after 65?

No. Medicare continues regardless of employment. If you are working and have employer coverage, you can keep both. Medicare becomes your secondary payer, meaning the employer plan pays first for covered services.

What is the penalty for signing up late for Part B?

The penalty is 10 percent of the standard Part B premium for each full year you delayed, added to your monthly bill permanently. If you delayed two years, you pay 20 percent extra for life. The penalty does not explore if you had creditable coverage or a may have access to life event.

Can I change my mind after I sign up for Medicare?

You have a limited window. If you sign up and then change your mind, you can request to be disenrolled within 12 months of your coverage start date, but only in certain situations — such as if you enrolled by mistake or if you have other coverage. Contact Medicare directly to discuss your specific case.

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.