Medicare starts at 65 for most people, but the exact date depends on your birthday and when you sign up

You become may be able to access for Medicare on the first day of the month in which you turn 65. If your birthday is the first of any month, that is your start date. If your birthday falls on any other day, Medicare begins on the first day of the following month. For example, if you turn 65 on March 15, your coverage starts April 1.

You do not have to wait until you turn 65 to sign up—in fact, you should not. Medicare has strict enrollment windows, and signing up late can cost you more in premiums for the rest of your life. The enrollment period that matters most runs from three months before you turn 65 through three months after, a total of seven months. If you miss this window, you may face permanent penalties.

Some people become may be able to access before 65 because of disability or end-stage renal disease. Those rules are different and are covered separately in the sections below.

Key Takeaways

  • Medicare coverage begins on the first of the month in which or after you turn 65, depending on your exact birthday.
  • You can sign up starting three months before you turn 65, and you should do so during this window to avoid late-enrollment penalties.
  • If you are still working and have health insurance through your employer, you may be able to delay Part B enrollment without penalty, but you must tell Medicare about your coverage.
  • People under 65 with disabilities or end-stage renal disease can become may be able to access for Medicare earlier, but they must meet specific requirements.
  • Signing up late for Part B or Part D can result in a permanent 10 percent increase in your monthly premium for each year you delayed.

How your birthday determines your Medicare start date

Medicare uses a straightforward rule: coverage begins on the first day of the month you turn 65 or the first day of the month after, whichever comes first. This means your exact start date depends only on which day of the month you were born.

If you were born on January 1, your Medicare coverage begins January 1 of the year you turn 65. If you were born on January 15, your coverage begins February 1. If you were born on January 31, your coverage also begins February 1, because there is no February 31. The rule is consistent: the first day of the month in which or when ready after your 65th birthday.

You should mark this date on your calendar and plan to enroll before it arrives. Waiting until after your coverage date to sign up does not delay your coverage—it just means you signed up late, which can trigger penalties.

The enrollment window: when you can and should sign up

Your Initial Enrollment Period (IEP) is a seven-month window centered on the month you turn 65. It runs from three months before your 65th birthday through three months after. During this time, you can sign up for Medicare Part A (hospital insurance) and Part B (medical insurance) without penalty, regardless of whether you are working or have other coverage.

The best time to enroll is during the three months before you turn 65. This gives Medicare time to process your process and have your coverage ready on your start date. If you wait until after your birthday month, you may have a gap in coverage or a delay in receiving your Medicare card.

If you miss your Initial Enrollment Period, you can still sign up during the General Enrollment Period, which runs January 1 through March 31 each year. However, coverage does not begin until July 1 of that year, and you will owe a permanent penalty on 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. That penalty stays with you for life.

Working past 65 and delaying Part B enrollment

If you are still working and covered by your employer's health insurance, you may not need to enroll in Medicare Part B right away. You can delay Part B enrollment without penalty as long as you have creditable coverage—health insurance through your current employer or your spouse's current employer that is at least as good as Medicare.

However, you must still enroll in Part A (hospital insurance) when you turn 65, even if you are working. Part A is free for most people and does not conflict with employer coverage. Delaying Part A can result in a penalty, and you cannot make up the time later.

If you choose to delay Part B because you are working, you must tell Medicare about your employer coverage when you eventually sign up. You will have an eight-month window after your employment ends or your coverage stops to enroll in Part B without penalty. After that window closes, the 10 percent annual penalty applies.

Medicare may be able to access before 65: disability and kidney disease

You can become may be able to access for Medicare before 65 if you have been receiving Social Security Disability Insurance (SSDI) for at least 24 months. Your Medicare coverage begins on the 25th month of your disability benefits, regardless of your age. If you are already receiving SSDI when you turn 65, you will automatically transition to regular Medicare at that time.

You can also become may be able to access for Medicare at any age if you have end-stage renal disease (ESRD)—permanent kidney failure requiring dialysis or a transplant. Coverage begins in the month you start dialysis or the month of your transplant, whichever comes first. If you are already on dialysis when you turn 65, you will transition to regular Medicare at that time.

People with ALS (amyotrophic lateral sclerosis) become may be able to access for Medicare when ready upon approval for SSDI, without the 24-month waiting period. If you have ALS, you do not have to wait two years.

What happens after you sign up

Once you enroll, Medicare will mail you a Medicare card showing your coverage effective date. This card arrives about two weeks before your coverage begins. Keep it in a safe place—you will need it when you see a doctor or go to the hospital.

Your coverage includes Part A (hospital insurance) and Part B (medical insurance) automatically. You will receive a bill for Part B premiums unless you are on Supplemental Security Income (SSI) or have very low income, in which case your state may pay your premiums. Part A has no monthly premium for most people.

After you enroll in Parts A and B, you have until December 31 of your Initial Enrollment Period to sign up for Part D (prescription drug coverage) without penalty. If you do not enroll in Part D when you first become may be able to access and you go without creditable drug coverage, you will owe a penalty when you do sign up. That penalty is 1 percent of the national average Part D premium for each month you were not covered, and it is permanent.

Signing up: where to go and what you need

You can enroll in Medicare through 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.

Have your Social Security number ready, along with information about any current health insurance you have. If you are still working, bring details about your employer's health plan so Medicare can confirm it is creditable coverage. If you are explore for the first time, the process usually takes 15 to 30 minutes.

If you are already receiving Social Security benefits, you may be enrolled in Medicare automatically. Check your Social Security account online or call Social Security to confirm. If you are not automatically enrolled, you must sign up yourself during your Initial Enrollment Period.

Frequently Asked Questions

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

Medicare coverage begins on the first day of the month after you turn 65. If you turn 65 on March 20, your coverage starts April 1. You should sign up during the three months before your birthday so there is no gap.

Can I delay Medicare if I am still working?

You can delay Part B if you have employer health insurance, but you must enroll in Part A at 65. When you leave your job or lose coverage, you have eight months to enroll in Part B without penalty. After that, a permanent 10 percent penalty applies to your Part B premium.

What is the penalty for signing up late?

If you miss your Initial Enrollment Period and do not have a valid reason for the delay, you owe a permanent 10 percent increase in your Part B premium for each year you were may be able to access but not enrolled. This penalty stays with you for life, even if you switch plans later.

Do I have to sign up for Part D when I turn 65?

You do not have to, but if you go without creditable drug coverage, you will owe a penalty when you do sign up. The penalty is 1 percent of the national average Part D premium for each month you were not covered, and it is permanent. Sign up during your Initial Enrollment Period to avoid it.

Will I be automatically enrolled in Medicare?

If you are already receiving Social Security benefits, you will be automatically enrolled in Parts A and B about three months before you turn 65. If you are not receiving Social Security, you must sign up yourself. Check your Social Security account online to confirm your enrollment status.