File for Medicare Part B during your Initial Enrollment Period or face a permanent penalty

Most people should sign up for Medicare Part B (medical insurance) when they first turn 65, during a window called your Initial Enrollment Period. This 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 other coverage that counts as "creditable," Medicare charges you a late enrollment penalty for as long as you have Part B — usually 10% more per month than the standard premium.

The penalty is permanent. It does not go away after a few years. This means if you wait until age 68 to sign up, you will pay that extra amount every month for the rest of your life, even if you only waited three years. The only way to avoid the penalty is to sign up during your Initial Enrollment Period or to have had coverage that Medicare counts as equal to Part B (called creditable coverage) during the months you were not enrolled.

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.
  • If you miss this window and do not have creditable coverage, you will pay a permanent 10% monthly penalty on top of your Part B premium for life.
  • Creditable coverage means employer health insurance, TRICARE, or certain other plans that Medicare recognizes as equal to Part B.
  • You can sign up for Part B through Social Security, Medicare.gov, or your local Social Security office, and the process takes about two weeks.
  • If you are still working and covered by your employer's plan, you may be able to delay Part B without penalty, but you must tell Medicare this when you do sign up.

Who must sign up during the Initial Enrollment Period

If you are turning 65 and do not have health insurance through an employer, a union, or a government program like TRICARE or the Veterans Health Administration, you should sign up for Part B during your Initial Enrollment Period. This applies whether you are retiring or still working — the rule is based on age, not employment status.

The only people who can safely wait past their Initial Enrollment Period are those with creditable coverage. Creditable coverage means you are covered by a health plan through your current employer or your spouse's current employer, or you have TRICARE (military health insurance), the Veterans Health Administration, or certain other plans that Medicare recognizes as equal to Part B. If you have any doubt whether your coverage counts, call Medicare at 1-800-MEDICARE before your Initial Enrollment Period ends.

What happens if you miss the important date

If you do not sign up during your Initial Enrollment Period and you do not have creditable coverage, you enter what Medicare calls a General Enrollment Period each year from January 1 to March 31. You can sign up then, but your coverage does not start until July 1 of that year — a gap of several months. More importantly, you will owe a late enrollment penalty.

The penalty is 10% of the standard Part B premium for each full 12-month period you were not enrolled and did not have creditable coverage. If the standard premium is $165 per month and you waited two years to sign up, your penalty would be 20% — an extra $33 per month added to your premium. This extra amount stays with you permanently, even if you switch plans or move to a different state.

There are very few exceptions to this penalty. Medicare may waive it only if you can show that you did not know you needed to sign up, or that Social Security or Medicare gave you incorrect information. straightforward forgetting or not understanding the important date does not count as grounds for a waiver.

How to sign up during your Initial Enrollment Period

You can sign up for Part B in three ways: online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office. Online is usually fastest — you can complete the process in about 15 minutes. By phone, expect to spend 20 to 30 minutes, and the wait time varies. In person, bring your Social Security card, proof of citizenship or legal residency, and proof of age (a birth certificate or passport).

When you sign up, Medicare will ask you to choose a start date for your coverage. If you sign up during the three months before you turn 65, your coverage can start the first day of the month you turn 65. If you sign up during the month you turn 65 or after, your coverage start date depends on when in the month you sign up — usually the first of the following month. Processing takes about two weeks, so plan ahead.

You will also need to decide whether you want to sign up for Part D (prescription drug coverage) at the same time. You are not required to take Part D when you turn 65, but if you wait and do not have creditable drug coverage, you will face a late enrollment penalty on Part D as well — 1% of the national average premium for each month you were late, also permanent.

Delaying Part B if you have employer coverage

If you are still working and covered by your employer's health plan, you may be able to delay Part B without penalty. This is called the Special Enrollment Period for people with employer coverage. To use it, you must be covered by an employer plan based on your current work (or your spouse's current work), and you must sign up for Part B within eight months of losing that coverage or retiring, whichever comes first.

The key word is "current" work. If you are retired and covered by a retiree health plan, that does not count — you should sign up for Part B during your Initial Enrollment Period. If you are unsure whether your plan qualifies, ask your employer's benefits office or call Medicare before your Initial Enrollment Period ends.

When you do sign up under this Special Enrollment Period, you must tell Medicare that you had employer coverage. Bring a letter from your employer or a copy of your health plan documents showing the dates you were covered. Without this proof, Medicare may assume you were late and charge you the penalty anyway.

What to do if you missed your important date

If your Initial Enrollment Period has already passed and you do not have creditable coverage, you can still sign up during the General Enrollment Period (January 1 to March 31 each year). Your coverage will start July 1 of that year. You will owe the late enrollment penalty unless you can show that you did not know you needed to sign up or that you received incorrect information from Social Security or Medicare.

To request a penalty waiver, you must submit a written request to Medicare explaining why you missed the important date. Send it to the address on your Medicare notice, or ask at your local Social Security office for the correct mailing address. Medicare will review your request, but approval is rare. Do not wait — sign up as soon as you realize you missed the important date, because the penalty grows larger the longer you wait.

If you are already on Medicare and realize you missed Part B, you can still sign up during any General Enrollment Period. Call 1-800-MEDICARE to confirm your options and start the process.

Understanding the Part B premium and how it changes

The standard Part B premium changes each year. In 2024, it is $165 per month for most people, but this amount increases annually based on inflation and changes in Medicare costs. If you have a higher income, you may pay an additional amount called an Income-Related Monthly Adjustment Amount (IRMAA), which can add $70 to $560 per month depending on your income and filing status.

The late enrollment penalty is calculated as a percentage of the standard premium at the time you sign up, not the premium from when you should have signed up. This means the penalty amount will also increase over time as the standard premium rises. If you delay signing up, both your base premium and your penalty will be higher when you finally enroll.

Frequently Asked Questions

Can I sign up for Part B after I turn 65 if I do not have other insurance?

Yes, but only during the General Enrollment Period (January 1 to March 31 each year), and your coverage will not start until July 1. You will also owe a permanent late enrollment penalty. It is much better to sign up during your Initial Enrollment Period, which gives you coverage starting the month you turn 65 and avoids the penalty entirely.

What if I was working and did not know I needed to sign up for Part B?

Not knowing is not usually grounds for a penalty waiver. However, if you can show that Social Security or Medicare gave you incorrect information, you may be able to request a waiver. Submit a written request to Medicare explaining what information you received and when. Approval is not may provide, but it is worth trying if you have documentation.

Does my spouse's coverage count as creditable coverage for me?

Only if you are covered under your spouse's employer health plan or TRICARE. If your spouse has Medicare, that does not count as creditable coverage for you. You must have your own coverage based on current employment or military service to delay Part B without penalty.

What happens to my late enrollment penalty if I switch Medicare plans?

The penalty stays with you. It does not disappear if you switch from Original Medicare to a Medicare Advantage plan, or vice versa. The penalty is attached to your Part B enrollment, not to a specific plan, and you will pay it every month for life unless Medicare waives it.

Can I sign up for Part B before I turn 65?

Yes. Your Initial Enrollment Period starts three months before the month you turn 65, so you can sign up as early as that date. Many people sign up two or three months before they turn 65 to make sure their coverage starts on time. Signing up early does not cost you anything extra and gives you peace of mind.