Medicare Part B Eligibility and Enrollment
Key Takeaways
- Medicare Part BMedicare Part B is medical insurance that covers Medicare-approved services — such as medically necessary treatment and preventive services — and certain other costs, like durable medical equipment. Medicare Part B is part of Original Medicare. is medical insurance.
- For most people, the first chance to enroll in Part B is their Initial Enrollment PeriodThe Initial Enrollment Period (IEP) is the seven-month period around your 65th birthday when most people are eligible for the first time to enroll in Medicare. ; this is a seven-month period around the month they turn 65
- If you’re working and have coverage through an employer when you turn 65, you may be able to delay enrollment. When that coverage ends, you can then enroll in Medicare during a Special Enrollment PeriodA Special Enrollment Period is an opportunity outside of a standard enrollment period in which your specific circumstances allow you an opportunity to make changes to your Medicare-related coverage. .
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Medicare Part B Eligibility
Medicare Part B is the part of Original Medicare that covers outpatient care and preventive care services. This also includes some medical equipment and therapy sessions.
U.S. citizens and permanent residents generally become eligible for Original Medicare — Parts A and B — when they turn 65. You are typically first eligible during your Initial Enrollment Period, which includes:
- Three months before you turn 65
- The month you turn 65
- Three months after you turn 65
Age isn’t the only qualifier, however; if you’re under 65 and meet any of these Medicare Part B eligibility requirements, you may be able to receive benefits:
- You have received disability benefits from the Social Security Administration for more than 24 months
- You have received disability benefits from the Railroad Retirement Board for more than 24 months
- You have End-Stage Renal Disease (ESRD)
- You have received a kidney transplant
If you have been diagnosed with Amyotrophic Lateral Sclerosis (ALS, also known as Lou Gehrig’s disease) and qualify for disability, you will be eligible for Medicare Part B the first month your disability payments begin. Unlike with other disabilities, you do not need to wait for 24 months.
Another special circumstance is for children with disabilities. Children with disabilities cannot receive Social Security disability benefits before the age of 18, which means they cannot enroll in Medicare parts A or B until they are 20 years old — unless their disability is ALS.
Is Part B Mandatory?
You don’t have to join Medicare Part B when you first become eligible, but if you don’t have coverage from another source (such as employer-provided insurance), you will pay a late enrollment penalty when you eventually sign up. So it may cost you more if you opt out and then change your mind later.
The late enrollment penalty for Medicare Part B is a 10% increase in your monthly premium for each 12-month period that you were eligible to enroll in Part B but didn’t. The longer you go without signing up for Medicare Part B, the higher your penalty will be. This penalty doesn’t go away, either — it will be added to your monthly Medicare Part B premium for as long as you have Part B coverage.
You may be able to avoid a late enrollment penalty if you:
- Are still working and eligible for employer benefits when you turn 65. Once your employment and those benefits end, you have eight months to sign up for Medicare Part B without a penalty.
- Enroll in Part B past your initial eligibility, but you have end-stage renal disease.
Is There an Income Limit for Part B?
There is no income limit for Medicare Part B, but your income will have an impact on what you pay in monthly premiums. More specifically, the earnings you reported two years prior will be used to determine what you pay for your Part B premium. For example, what you pay in 2025 is based on your 2023 income. Monthly premiums are set for certain income ranges.
For a single person, here are the annual income limits and monthly premium amounts for 2025:
- $106,000 or less: $185
- Greater than $106,000 to $133,000: $259
- Greater than $133,000 to $167,000: $370
- Greater than $167,000 to $200,000: $480.90
- Greater than $200,000 to less than $500,000: $591.90
- $500,000 or more: $628.90
For married couples filing jointly, here are the income limits and premium amounts for 2025:
- $212,000 or less: $185
- Greater than $212,000 to $266,000: $259
- Greater than $266,000 to $334,000: $370
- Greater than $334,000 to $400,000: $480.90
- Greater than $400,000 to less than $750,000: $591.90
- $750,000 or more: $628.90
If you can’t afford this premium amount, there are a number of programs that can help. Many states offer Medicare Savings Programs that can help you cover the cost of your premium if your income is below a certain threshold, or if you have certain disabilities.
Medicare Part B Enrollment
In most cases, your first chance for Medicare Part B enrollment begins three full calendar months before you turn 65. This is known as your Initial Enrollment Period (IEP). If you miss your IEP, or want to change, drop or add your coverage later, there are a few other Medicare enrollment periods.
When Can I Sign Up for Medicare Part B?
Figuring out when to sign up for Medicare Part B is just as important as learning how. When planning, keep in mind there are typically three main times when you can enroll in Medicare Part B. Two of them, the Initial Enrollment Period (IEP) and Special Enrollment Periods (SEP), are specific to your situation. The third option, the General Enrollment Period, is the same for everyone and is built into the annual Medicare calendar. Here’s an overview of how they work:
- Initial Enrollment Period (IEP): your first chance to enroll in Medicare; the seven-month IEP includes your birth month, plus three months before and after. However, if you were born on the first of the month, then your IEP starts four calendar months before the month you turn 65 and closes two calendar months after. If you enroll during your IEP, you won’t pay an enrollment penalty.
- General Enrollment Period (GEP): this is your chance to enroll if you missed your IEP. The GEP is held each year from January 1 to March 31. Plans purchased during the GEP begin the first of the following month.
- Special Enrollment Period (SEP): an enrollment period that’s granted by Medicare for certain life events. This generally includes losing employer health coverage. If you qualify for a SEP when you lose other coverage, an eight-month enrollment period will open when that coverage ends. You can choose a Part B plan without penalty during the SEP.
Do I Have to Apply for Medicare Part B if I’m Still Working?
Under certain circumstances, you may choose to delay your Medicare Part B enrollment. If you’re still receiving health insurance from your employer when you turn 65, you can often put off your enrollment until you no longer have group coverage. When that happens, an eight-month Special Enrollment Period will open, and you can sign up for Part B without penalty.
Your decision on whether to enroll in Medicare when you have employer coverage will need to come down to the size of your employer, as smaller companies may receive help from Medicare to cover your health insurance benefits.
Here’s how it works:
- If your company has 20 or more employees: Larger companies are typically the “primary payer” on coverage for workers who are 65 or older. This leaves Medicare Part B as the “secondary payer.” In this case, you may be able to delay your Part B enrollment.
- If your company has fewer than 20 employees: Medicare will typically be the primary payer for your health care. This helps relieve some of the cost burdens for smaller companies. In this case, enrolling in Medicare Part B on top of your group coverage may make sense.
How Do You Add Medicare Part B?
Medicare enrollment is handled by the Social Security Administration (SSA). Whether you’re looking to enroll in Medicare when you turn 65, or you need to add Part B later, there are several ways to sign up for your benefits.
- Visit a local SSA office
- Over the phone at 1-800-772-1213
- Online at ssa.gov
Can I Sign Up for Part B Medicare Online?
You can fill out your Medicare Part B application on the Social Security Administration website, or you can print off your Medicare Part B forms to fill out by hand. If you print your forms, you can mail your Medicare Part B application in, or deliver it to a local office in person.
What Documents Do I Need To Enroll in Medicare Part B?
When you enroll in Medicare Part B, you’ll want to have some basic info handy. This can include:
- Your date and place of birth
- Your Social Security number
- Dates and places of all of your marriages
- Dates of divorces or deaths
- Citizenship status
- Employment and earnings records
If you’ve delayed enrollment because you had other coverage, you may also need to prove that you had creditable coverage instead of Part B. You may be asked to provide one or more of the following:
- W-2s that show you’re contributions for health insurance
- Pay stubs that reflect health insurance enrollment
- Health insurance cards with policy effective dates
- Receipts showing you paid monthly premiums
- Income tax returns
Depending on your individual situation, you may need additional documentation.
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Switching to Medicare Advantage
Medicare Advantage plans are offered by private insurance carriers to substitute for Original Medicare. Plans must at least match the coverage of Medicare Part A and Part B, but may include additional benefits. Most people on Medicare Advantage plans are still responsible for paying the Part B premium as well as costs like their plan’s deductible and copayment.
You must enroll in both Medicare Part A and Part B before switching to a Medicare Advantage plan. To get the most out of your benefits, you may need to visit doctors and pharmacies that are in your plan’s provider network, so learn all the details before choosing a plan.
Sources
- How Do I Sign Up for Medicare? Medicare.gov.
- Medicare Benefits. SSA.gov.
- Who is eligible for Medicare? HHS.gov.
- Original Medicare (Part A and B) Eligibility and Enrollment. CMS.gov.
- What does Part B of Medicare (Medical Insurance) cover? HHS.gov.
- Introduction to Social Security. SSA.gov.
- How is Medicare Funded? Medicare.gov.
- Your Medicare Coverage. Medicare.gov.
- Apply for benefits. SSA.gov.
- Understanding Medicare Advantage plans. Medicare.gov.