Enroll in Medicare Part B During Your Initial Enrollment Period or Face Permanent Penalties

You should enroll in Medicare Part B when you first become may be able to access at age 65, unless you have coverage through your current employer that is at least as good as Medicare. Your Initial Enrollment Period runs for seven months: three months before the month you turn 65, the month you turn 65, and three months after. If you miss this window and do not have employer coverage, you will pay a higher premium for Part B for as long as you have Medicare—there is no way to remove this penalty later.

Part B covers doctor visits, outpatient care, medical equipment, and preventive services. It is separate from Part A (hospital care), which most people get automatically. You must actively choose Part B; it does not enroll you on its own. The standard monthly premium for Part B in 2024 is $164.90, though it varies by income and changes each year.

Key Takeaways

  • Your Initial Enrollment Period is seven months long—three months before you turn 65, the month you turn 65, and three months after—and missing it triggers a permanent 10 percent premium increase for each year you delayed.
  • If you are still working and covered by your employer's health plan, you can delay Part B without penalty as long as the employer plan covers at least 20 employees.
  • You enroll through Social Security, Medicare.gov, or your local Social Security office—not through your doctor or insurance company.
  • Part B premiums are deducted from your Social Security check if you receive benefits, or billed separately if you do not yet collect Social Security.

When You Turn 65 Without Employer Coverage

If you are not working or your employer does not offer health insurance, enroll in Part B during your Initial Enrollment Period. The easiest way is online at Medicare.gov starting three months before your 65th birthday. You can also call Social Security at 1-800-772-1213 or visit your local Social Security office in person.

Enrollment takes about 15 minutes online. You will need your Social Security number and information about any current coverage. Part B becomes effective the first day of the month you turn 65 if you enroll before that month ends. If you enroll after your birthday month, coverage starts the first day of the following month.

When You Are Still Working at 65

If you are employed and your employer offers health insurance, you can delay Part B without penalty. This applies only if your employer has at least 20 employees and you are covered under their plan. You do not need to enroll in Part B while you have this coverage.

Once you leave your job or lose employer coverage, you have eight months to enroll in Part B without penalty. This is called your Special Enrollment Period. You must enroll within this window; after eight months, the permanent penalty applies. When you do enroll, bring proof that you had employer coverage—your insurance card or a letter from your employer stating the coverage dates and number of employees.

When You Miss Your Initial Enrollment Period

If you did not enroll during your Initial Enrollment Period and you do not have employer coverage, you can still enroll in Part B, but you will pay a 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. This penalty is permanent—it stays with you for life, even if you later switch plans.

For example, if you turned 65 in January 2020 and did not enroll until January 2023, you delayed for three years. Your penalty would be 30 percent of the standard premium, added to your monthly bill forever. You can enroll in Part B during the General Enrollment Period, which runs from January 1 to March 31 each year. Coverage begins July 1 of that year.

When You Are on Medicare Advantage or Medigap

If you already have Medicare Advantage (Part C) or a Medigap supplemental plan, you already have Part B—it is included in both. You do not need to take a separate action. Your Advantage or Medigap plan works alongside Part A and Part B to cover your medical costs.

If you are switching from Advantage to Original Medicare or from one Medigap plan to another, check your plan's rules about timing. Some changes require you to drop your current plan before enrolling in a new one. Contact your current plan's customer service before making changes to avoid a gap in coverage.

When You Receive Social Security Before 65

If you receive Social Security retirement or disability benefits before age 65, you are automatically enrolled in Part A and Part B three months before you turn 65. You do not need to do anything. Your Part B premium will be deducted from your Social Security check starting the month you turn 65.

If you do not want Part B, you must decline it in writing before your coverage starts. Contact Social Security or Medicare to request a form. Declining Part B is rare and usually only makes sense if you have employer coverage that is better than Medicare. If you decline and later change your mind, you will face the permanent penalty unless you have a may have access to reason.

When You Are on Disability Before 65

If you receive Social Security Disability Insurance (SSDI), you are automatically enrolled in Part A and Part B after you have been on disability for 24 months. You do not need to enroll yourself. Part B coverage begins automatically; your premium is deducted from your disability check.

If you are working while on SSDI and have employer coverage, you can request to delay Part B. Contact Social Security to explain your situation. Once your employer coverage ends, you have eight months to enroll in Part B without penalty.

Frequently Asked Questions

What happens if I enroll in Part B but do not use it?

You still pay the monthly premium whether you use it or not. Part B is worth having even if you are healthy, because it covers preventive care like annual wellness visits and screenings at no additional cost. If you go without it and later need a doctor, you will face the permanent penalty on top of the current premium.

Can I enroll in Part B online, or do I have to go in person?

You can enroll online at Medicare.gov, by phone with Social Security, or in person at a Social Security office. Online is fastest—you can complete it in 15 minutes. Phone and in-person enrollment take longer but work just as well.

Do I have to enroll in Part A and Part B at the same time?

No. Part A (hospital insurance) is usually automatic if you or your spouse paid Medicare taxes while working. Part B (doctor and outpatient care) requires you to actively enroll. You can have Part A without Part B, though most people get both.

What if I turn 65 in the middle of the month—when does my coverage start?

Coverage starts the first day of the month you turn 65 if you enroll before that month ends. If you enroll after your birthday month, coverage starts the first day of the following month. For example, if you turn 65 on June 15 and enroll in June, coverage begins June 1. If you enroll in July, coverage begins August 1.

Will my Part B premium change after I enroll?

Yes. Part B premiums increase each year and are announced in the fall. Your premium may also be higher if your income is above a certain level—this is called Income-Related Monthly Adjustment Amount (IRMAA). Social Security will notify you if your premium changes.