Medicare Part B is not required, but skipping it usually costs you more later

You do not have to enroll in Medicare Part B (medical insurance that covers doctor visits, outpatient care, and some preventive services). However, if you delay enrollment without a valid reason, you will pay a permanent penalty on your Part B premium for as long as you have Medicare. The penalty is 10 percent for each 12-month period you were may be able to access but did not sign up. For most people, the math makes Part B worth taking when you first become may be able to access, even if you think you will not use it much.

The decision to enroll depends on your age, your current health coverage, and whether you can afford to pay the penalty later. If you have employer coverage or other health insurance when you turn 65, you may have a window to delay Part B without penalty. If you do not, the penalty clock starts when ready.

Key Takeaways

  • You must enroll in Part B during your Initial Enrollment Period (the seven-month window around your 65th birthday) or pay a permanent 10 percent penalty on your premium.
  • If you have employer health coverage when you turn 65, you can delay Part B without penalty as long as you enroll within eight months of losing that coverage.
  • Part B covers doctor visits, lab work, imaging, and preventive care — things that add up quickly if you pay out of pocket.
  • The monthly premium for Part B varies by income; higher earners pay more through Income-Related Monthly Adjustment Amounts (IRMAA).
  • If you decide not to enroll, you must actively decline during your enrollment period; silence counts as a missed important date.

When you can delay Part B without a penalty

You can postpone Part B enrollment without penalty if you have creditable coverage — health insurance through an employer, a union, or a spouse's employer. This coverage must be active when you turn 65. The rule is called the Special Enrollment Period, and it gives you eight months after your coverage ends to sign up for Part B without penalty.

The clock starts the month your employer coverage ends, not the month you turn 65. If you retire at 66 and lose coverage then, you have until eight months after that date. If you miss this window, the penalty applies. You will also need to show proof that you had creditable coverage — your employer or health plan can provide a letter stating the dates and type of coverage.

If you are still working at 65 and your employer has 20 or more employees, you may not need Part B at all while you work. Medicare becomes secondary to your employer plan. However, you should still enroll in Part A (hospital insurance) at 65, even if you skip Part B, because Part A has no premium and no penalty for late enrollment.

The cost of delaying Part B

The standard Part B premium in 2024 is $164.90 per month for most people, though this changes each year. If you delay enrollment by three years without a valid reason, your premium increases by 30 percent — that is 10 percent for each year you were may be able to access but did not enroll. That 30 percent increase stays with you for life.

Over time, the penalty adds up significantly. If you delay three years and then live another 20 years on Medicare, you will have paid thousands of dollars in extra premiums. The penalty does not go away when you finally enroll; it is permanent. Even if your circumstances change and you suddenly need Part B, you cannot undo the penalty by enrolling later.

Higher-income beneficiaries also pay an additional surcharge called IRMAA (Income-Related Monthly Adjustment Amount). This is based on your tax return from two years prior. If your income exceeds certain thresholds, your Part B premium can be two to three times the standard amount. Delaying Part B does not avoid IRMAA; it only adds the late-enrollment penalty on top of it.

What Part B actually covers

Part B covers doctor office visits, emergency room care, urgent care, lab work, X-rays, imaging (CT scans, ultrasounds, MRIs), physical therapy, and most preventive services like cancer screenings and vaccinations. It also covers some equipment like wheelchairs, walkers, and oxygen supplies. Part B does not cover dental, vision, or hearing aids — those require separate coverage.

If you have a chronic condition like diabetes or heart disease, Part B covers the ongoing management: regular doctor visits, blood tests, and monitoring. Without it, you pay the full cost of each visit and test out of pocket. Even people who are generally healthy often need imaging or lab work at some point, and these costs add up quickly without insurance.

Part B comes with a yearly deductible (currently $240) and then you pay 20 percent of the cost of most services after that. Many people add a Medigap policy (supplemental insurance) to cover the deductible and coinsurance, which is why Part B premiums are only part of the total cost.

Your enrollment window and what happens if you miss it

Your Initial Enrollment Period is seven months long: it starts three months before the month you turn 65, includes the month you turn 65, and ends three months after. During this time, you can enroll in Part B with no questions asked and no penalty, even if you do not need it yet.

If you do not enroll during this window and you do not have creditable coverage, you enter a General Enrollment Period each year from January 1 to March 31. You can enroll then, but the late-enrollment penalty applies. Your coverage would start July 1 of that year, meaning you would have no Part B coverage from April through June.

If you want to decline Part B entirely, you must do so actively — usually by signing a form stating you are turning it down. straightforward not enrolling does not count as a choice; it counts as a missed important date. Contact Social Security or Medicare to confirm whether you need to submit a formal declination or whether your situation qualifies for a Special Enrollment Period.

Income affects your Part B cost

Part B premiums are not the same for everyone. If your modified adjusted gross income (MAGI) from your tax return from two years ago exceeds certain thresholds, you pay more through IRMAA. In 2024, single filers earning over $97,000 and married couples earning over $194,000 pay higher premiums. The surcharge can add $70 to $350 per month depending on your income level.

IRMAA is recalculated each year based on your prior-year tax return. If your income drops — because you retire, sell a home, or have other changes — you can request a Life-Changing Event review to lower your premium. You have to report the change within 60 days of when it happens.

What to ask your doctor or Medicare counselor

Before you decide to skip Part B, ask your doctor whether you will need regular office visits, lab work, or imaging in the next few years. Ask what an office visit costs without insurance at their practice, and what a basic lab panel or imaging study would run. This gives you a real number to compare against the Part B premium.

If you have employer coverage, ask your benefits department whether it is creditable coverage under Medicare rules and when you lose it. Ask them to provide a letter stating the dates and type of coverage, which you will need if you delay Part B enrollment.

Contact Medicare at 1-800-MEDICARE or visit Medicare.gov to confirm your Initial Enrollment Period dates and to understand whether your situation qualifies for a Special Enrollment Period. A State Health Insurance information Program (SHIP) counselor can also walk you through the decision at no cost — find your local SHIP at shiptalk.org.

Frequently Asked Questions

Can I enroll in Part B after I turn 65 if I did not sign up during my Initial Enrollment Period?

Yes, during the General Enrollment Period (January 1 to March 31 each year), but you will pay a permanent late-enrollment penalty on your premium. Your coverage would start July 1. If you have creditable employer coverage, you have eight months after it ends to enroll without penalty.

What if I have Veterans benefits or TRICARE instead of employer coverage?

TRICARE and VA coverage are considered creditable coverage. You can delay Part B without penalty as long as you enroll within eight months of losing that coverage. Get a letter from your VA or TRICARE office documenting your coverage dates.

Do I have to pay Part B premiums if I am still working at 65?

If your employer has 20 or more employees and you are actively working, Medicare is secondary to your employer plan. You do not need Part B while you work, but you should still enroll in Part A at 65. Once you retire and lose employer coverage, you have eight months to enroll in Part B without penalty.

Will my Part B premium go down if I wait until I am older to enroll?

No. The premium does not decrease with age. The only thing that changes is the late-enrollment penalty, which increases the longer you wait. Enrolling at 65 costs less over your lifetime than delaying and paying the penalty for years.

What happens if I enroll in Part B and then decide I do not want it?

You can drop Part B, but you will pay the late-enrollment penalty if you enroll again later. Dropping Part B is permanent unless you have a may have access to life event. Talk to Medicare before you drop it to understand the long-term cost.