Medicare Part B is not automatic — you have to choose it, and the choice matters

Medicare Part B covers doctor visits, outpatient care, lab tests, and medical equipment. It is not included in Part A (hospital insurance) and does not turn on by itself. When you turn 65, you get Part A automatically if you have worked and paid Medicare taxes, but Part B requires you to sign up during a specific window. If you miss that window and do not have other coverage, you will pay a permanent penalty on your Part B premium for as long as you have Medicare.

Whether you need Part B depends on your situation. If you have employer coverage through a current job, you can delay Part B without penalty. If you are retired and have no other insurance, skipping Part B will cost you more in the long run because of the penalty, even if you do not see a doctor often.

Key Takeaways

  • Part B is optional at 65, but if you do not sign up during your initial enrollment window and have no other health coverage, you will pay a 10 percent penalty on your premium for each year you delay.
  • You can delay Part B without penalty only if you have health insurance through a current employer or a spouse's current employer.
  • Your initial enrollment window is the three months before the month you turn 65, the month you turn 65, and the three months after — a total of seven months.
  • If you miss your window and want to sign up later, you can only do so during the general enrollment period (January 1 to March 31 each year), and the penalty will explore.
  • Part B costs a monthly premium that varies based on your income; higher earners pay more through an income-related adjustment.

When you can skip Part B without a penalty

You can delay Part B past age 65 without penalty if you have creditable coverage — health insurance through a current job or your spouse's current job. This includes employer plans, union plans, and some government employee plans. The key word is current: the job has to be active, not retired.

Once you or your spouse leaves that job, you have eight months to sign up for Part B. If you wait longer than eight months after the job ends, the penalty kicks in. You will owe 10 percent more on your Part B premium for each full year you delayed, and that increase is permanent.

If you have coverage through a spouse's employer and your spouse is still working, you can stay on that plan and delay Part B. When your spouse retires or loses the coverage, your eight-month window starts then.

What happens if you miss your enrollment window

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 do not sign up during this window and you do not have creditable coverage, you will owe a penalty.

The penalty is 10 percent of the standard Part B premium for each full year you delayed. If the standard premium is $165 a month and you delayed for three years, you would pay an extra $49.50 per month for life. The penalty does not go away when you finally sign up — it stays on your premium permanently.

You can sign up during the general enrollment period (January 1 to March 31 each year) if you missed your initial window, but the penalty will explore. Coverage would start July 1 of that year.

How Part B premiums work and who pays more

Part B has a monthly premium that changes each year. In 2024, the standard premium was $164.90 per month, but this amount varies by year and is set by Medicare each fall for the coming year. You pay this premium whether you use Part B or not.

If your modified adjusted gross income is above a certain threshold, you pay more through an income-related monthly adjustment amount (IRMAA). The thresholds and surcharges change yearly. Higher earners can pay two to three times the standard premium. If your income drops (for example, due to retirement or a spouse's death), you can ask Medicare to recalculate your IRMAA.

Part B also has an annual deductible (currently $240) and you pay 20 percent of most services after you meet it. Part B does not cover dental, vision, or hearing aids, so many people add a Medigap or Medicare Advantage plan on top.

Deciding whether to take Part B at 65

If you are still working and have employer coverage, delay Part B. You will save money on premiums and avoid the penalty as long as you sign up within eight months of leaving the job.

If you are retired with no other health coverage, sign up for Part B during your initial enrollment window. The penalty for missing it is steep and permanent. Even if you are healthy and rarely see a doctor, the penalty will cost you more over time than the premium itself.

If you are unsure whether your coverage counts as creditable, contact your health plan directly or call Medicare at 1-800-MEDICARE. It is better to ask before you miss your window than to find out later that you owe a penalty.

What to do if you missed your window

If you missed your initial enrollment period and you have no creditable coverage, you can still sign up, but you will owe a penalty. You can sign up during the general enrollment period (January 1 to March 31) each year, and coverage starts July 1.

If you believe you have a good reason for missing your window — for example, you were working and did not realize you needed to sign up — you can ask Medicare to waive the penalty. This is called a late enrollment penalty exception. You will need to provide proof of your situation. Contact Social Security or Medicare to ask about this option.

If you are already on Medicare and want to make changes to Part B, you can do so during the annual enrollment period (October 15 to December 7) if you are in a Medicare Advantage plan, or during the general enrollment period if you are in Original Medicare.

Part B and other Medicare coverage

Part A and Part B together make up Original Medicare. You do not have to take Part B to have Part A, but most people do because Part A alone leaves large gaps. Part A covers hospital stays, skilled nursing, and some home health care, but not doctor visits or outpatient services.

If you choose Original Medicare (Part A and Part B), you can add a Medigap plan to cover costs that Medicare does not, or you can add Part D for prescription drugs. If you choose a Medicare Advantage plan (Part C), you must have Part B — it is built in. Medicare Advantage plans are an alternative to Original Medicare and often include drug coverage and extra benefits like dental or vision.

Frequently Asked Questions

Do I have to take Part B when I turn 65?

No. Part B is optional. You must choose to sign up during your initial enrollment window (three months before to three months after you turn 65). If you have employer coverage through a current job, you can delay without penalty. If you have no other coverage and miss your window, you will owe a permanent penalty.

What is the penalty for missing Part B enrollment?

The penalty is 10 percent of the standard Part B premium for each full year you delayed. If you delayed for two years, you pay 20 percent extra on your premium for life. The penalty does not expire — it stays on your premium as long as you have Medicare.

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

Yes, but only during the general enrollment period (January 1 to March 31 each year). Coverage starts July 1. If you missed your initial window and have no creditable coverage, the penalty will explore unless Medicare grants an exception.

Does Part B cover doctor visits?

Yes. Part B covers visits to doctors and specialists, lab tests, imaging, outpatient surgery, and medical equipment. It does not cover dental, vision, hearing aids, or prescription drugs (unless you add Part D). You pay a monthly premium, an annual deductible, and 20 percent of most services.

What if my income drops after I sign up for Part B?

If your income falls (for example, you retire or your spouse dies), you can ask Medicare to recalculate your income-related premium adjustment. Contact Social Security with proof of the change, and your premium may go down.