You can sign up for Medicare Part B through Medicare.gov, but the process depends on when you're may be able to access and whether you already have Part A

Medicare Part B covers doctor visits, outpatient care, and medical equipment. If you're turning 65 or becoming may be able to access through disability or end-stage renal disease, you'll need to enroll in Part B during your may be able to access window. The fastest way is through Medicare.gov, where you can complete enrollment in about 15 minutes if you have your Social Security number and Medicare number ready.

The online process works best if you're enrolling during your initial may be able to access period — the three months before the month you turn 65, the month itself, and three months after. If you're past that window, you can still enroll online, but you may face a late enrollment penalty that increases your premium permanently.

Key Takeaways

  • Go to Medicare.gov, click "Sign up for Medicare," and log in with your username or create a new account to start enrollment.
  • You'll need your Social Security number, date of birth, citizenship or immigration status, and current contact information to complete the form.
  • Part B enrollment takes effect on the first day of the month after Medicare receives your request, or the first of the month you turn 65 if you enroll during your initial period.
  • If you miss your initial enrollment window, you can still enroll online, but your premium may be 10 percent higher for each full year you delayed.
  • You can also call 1-800-MEDICARE or visit your local Social Security office if you prefer not to enroll online.

Step-by-step: enrolling through Medicare.gov

Start at Medicare.gov and look for the "Sign up for Medicare" button on the homepage. Click it and you'll be taken to a login page. If you don't already have a Medicare.gov account, select "Create an account" and enter your email address, a password, and your Social Security number. Medicare will verify your identity and send you a confirmation email.

Once you're logged in, select "Enroll in Part B" from the menu. You'll fill out a form with your personal information: full legal name, date of birth, citizenship or immigration status, and current mailing address. Have your Medicare card or Social Security card nearby — you'll need your Medicare number if you already have Part A. The form also asks whether you have other health insurance through an employer or union, which affects when your coverage starts.

Review your answers carefully before submitting. Medicare will show you a confirmation page with an process number — write this down or take a screenshot. You'll also receive a confirmation email. Keep both for your records, as you may need the process number if you contact Medicare later with questions.

What happens after you submit your enrollment

Medicare processes online enrollments within 7 to 10 business days. You don't need to do anything while you wait — Medicare will contact you only if they need more information. Your Part B coverage will start on the first day of the month after Medicare receives your request, unless you enrolled during your initial may be able to access period (the three months before, during, or after the month you turn 65), in which case coverage starts the first of the month you turn 65.

About two weeks before your coverage starts, you'll receive a new or updated Medicare card in the mail showing your Part B coverage. Your first premium payment is usually taken from your Social Security check automatically, unless you chose a different payment method during enrollment. If you have questions about your coverage start date or premium, you can call 1-800-MEDICARE and reference your process number.

When you cannot enroll online and need to call instead

Online enrollment works for most people, but some situations require a phone call to 1-800-MEDICARE. If you're a non-citizen or your immigration status is unclear, Medicare may need to verify your information by phone before processing your request. If you're enrolling more than three years after your initial may be able to access period, you may also need to speak with someone to confirm you understand the late enrollment penalty.

You can also visit your local Social Security office in person if you prefer. Bring your Social Security card, proof of citizenship or immigration status, and proof of your current address (a utility bill or lease works). Social Security staff can submit your Part B enrollment request on the spot, and you'll receive a receipt with your process number.

Late enrollment penalties and how they work

If you enroll in Part B after your initial may be able to access period ends, your monthly premium increases by 10 percent for each full year you delayed. This penalty is permanent — it stays on your premium for as long as you have Medicare Part B. For example, if you were may be able to access at 65 but didn't enroll until age 68, you'd pay a 30 percent penalty on top of your regular premium.

The only way to avoid this penalty is to have had creditable coverage — health insurance through an employer, union, or spouse's employer — during the time you weren't enrolled in Part B. If you did, you can enroll online and tell Medicare about your creditable coverage. You'll need to provide the name of the employer or plan and the dates you were covered. Medicare will review this information and waive the penalty if your coverage meets their standards.

What to do if your online enrollment doesn't go through

If you submit your enrollment and don't receive a confirmation email within a few hours, check your spam folder first — confirmation emails sometimes get filtered. If it's not there, log back into Medicare.gov and check your account status. You should see your enrollment request listed under "My applications and claims." If the status shows "In progress," Medicare is still processing it and you don't need to do anything.

If the status shows "Incomplete" or "Denied," there's usually a message explaining why. Common reasons include a mismatch between the name on your Social Security record and the name you entered, or a citizenship verification issue. Click on the process to see the specific problem, and you can either correct it and resubmit online or call 1-800-MEDICARE for help. Have your process number ready when you call.

Frequently Asked Questions

Do I have to enroll in Part B if I'm still working at 65?

No, if you or your spouse are still working and have health insurance through that job, you can delay Part B enrollment without penalty. You'll need to enroll within eight months after your employment ends or your coverage stops, whichever comes first. When you do enroll online, tell Medicare about your employer coverage so they don't explore a late penalty.

Can I enroll in Part B on Medicare.gov if I don't have a computer?

Yes. Call 1-800-MEDICARE and a representative can help you enroll over the phone, or visit your local Social Security office and staff there can enroll you in person. Both options are free and take about 15 minutes.

What if I enrolled in Part B but want to cancel it?

You can cancel Part B by calling 1-800-MEDICARE or visiting your Social Security office. Cancellation usually takes effect at the end of the month you request it. Be aware that if you cancel and later want to re-enroll, you may face a late enrollment penalty unless you have a valid reason, such as employer coverage.

Will I owe money for Part B coverage before my enrollment is processed?

No. Your Part B coverage and premiums don't start until the month Medicare approves your enrollment. You won't owe anything for the time between when you submit your request and when your coverage begins.

Can I change my mind about Part B after I enroll online?

Yes, you have a limited time to cancel. If you enroll during your initial may be able to access period, you can cancel within three months and avoid any premium charges. If you enroll after that window, you can still cancel, but you may owe premiums for the months your coverage was active.