How to Sign Up for Medicare Part B Online and Other Ways to Enroll

Yes, you can sign up for Medicare Part B online through Medicare.gov, but only during certain times of the year

You can enroll in Medicare Part B online at Medicare.gov during your Initial Enrollment Period (the seven-month window that starts three months before the month you turn 65) or during the General Enrollment Period (January 1 to March 31 each year). Outside these windows, online enrollment is not available unless you have a may have access to life event — such as losing employer coverage, moving to a new state, or becoming a U.S. citizen.

If you miss your Initial Enrollment Period and do not have a may have access to reason, you can still sign up during General Enrollment, but you may face a permanent late penalty on your Part B premium. The penalty is 10 percent for each full year you delayed enrollment after your Initial Enrollment Period ended.

Key Takeaways

Online enrollment through Medicare.gov works only during your Initial Enrollment Period (seven months centered on your 65th birthday) or the General Enrollment Period (January 1 to March 31).
If you enroll late without a may have access to reason, you will pay a 10 percent penalty on your Part B premium for as long as you have Medicare.
You can also sign up by phone (1-800-MEDICARE), by mail using Form CMS-40B, or in person at your local Social Security office.
If you are still working and covered by employer health insurance, you may be able to delay Part B enrollment without penalty through your employer's creditable coverage rules.

How to enroll in Part B online at Medicare.gov

Go to Medicare.gov and sign in with your username and password, or create a new account using your email address. Once logged in, look for the "Enrollment and Plans" section and select "Enroll in Original Medicare." Follow the prompts to review your coverage options and confirm your Part B enrollment.

The online process takes about 15 to 20 minutes. You will need your Social Security number, date of birth, and information about any current health coverage. After you submit, you should receive a confirmation number on screen and by email. Your coverage typically starts the first day of the month after you enroll, though this depends on when you submit your request.

When you cannot enroll online and what to do instead

If you are outside your enrollment window and do not have a may have access to life event, Medicare.gov will not let you enroll online. In this case, you have three other routes: phone, mail, or in person.

By phone: Call 1-800-MEDICARE (1-800-633-4227). Representatives are available Monday through Friday, 8 a.m. to 8 p.m. Eastern time. Have your Social Security number and any current insurance information ready. The call usually takes 10 to 15 minutes, and you will receive a confirmation number before you hang up.

By mail: read or request Form CMS-40B (process for Enrollment in Part B) from Medicare.gov or call 1-800-MEDICARE to have it mailed to you. Fill it out, sign it, and mail it to the address listed on the form. Processing takes two to four weeks from the date Medicare receives it.

In person: Visit your local Social Security office. Bring your Social Security card, proof of citizenship or legal residency, and proof of your current address. You can find your nearest office at ssa.gov/locator. Social Security staff can submit your Part B enrollment request on the spot.

What counts as a may have access to life event for enrollment outside the normal windows

A may have access to life event gives you a Special Enrollment Period — usually 60 days — to sign up for Part B outside the regular enrollment windows without facing a late penalty. Common may have access to events include losing employer health coverage, moving to a new state, becoming a U.S. citizen, or having a change in your Medicaid status.

If you believe you have a may have access to event, call 1-800-MEDICARE and explain your situation. A representative will determine whether you are may be able to access for a Special Enrollment Period and, if so, will help you enroll right away. Keep documentation of the event (such as a letter from your employer saying coverage ended) in case Medicare asks for proof later.

How to avoid the Part B late penalty

The most common way to avoid the penalty is to enroll during your Initial Enrollment Period. If you are still working and covered by your employer's health plan, you may be able to delay Part B without penalty through creditable coverage rules. This means your employer plan is considered as good as or better than Medicare Part B.

When you leave your job or lose employer coverage, you have eight months from the date coverage ends to sign up for Part B without penalty. This eight-month window is separate from your Initial Enrollment Period, so if you miss both, the penalty applies. Document the date your employer coverage ended — you will need it to prove you enrolled within the eight-month window.

If you are not sure whether your employer plan qualifies as creditable coverage, ask your employer's benefits department or call 1-800-MEDICARE. Getting this answer before you turn 65 can save you thousands of dollars in penalties over time.

What happens after you enroll online

After you submit your enrollment online, Medicare sends a confirmation email within a few minutes. Your Part B coverage usually begins on the first day of the month after you enroll, though if you enroll between the 1st and 15th of a month, coverage may start that same month.

Your Medicare card will arrive in the mail within two to three weeks. Until it arrives, you can print a temporary notice of enrollment from your Medicare.gov account to show to doctors or hospitals. Your Part B premium will be deducted from your Social Security check each month, or you can choose to pay by mail or online bank transfer if you do not receive Social Security.

Frequently Asked Questions

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

Yes, you have until the end of the calendar year to cancel Part B if you enrolled during your Initial Enrollment Period or a Special Enrollment Period. If you enrolled during the General Enrollment Period (January 1 to March 31), you can cancel by the end of that same calendar year, and coverage ends December 31. Call 1-800-MEDICARE to request cancellation.

What if I miss my Initial Enrollment Period by just a few days?

Unfortunately, the seven-month window is fixed and does not extend. If you miss it, you will need to wait for the General Enrollment Period (January 1 to March 31) to enroll, and you will face a late penalty unless you have a may have access to life event. Contact 1-800-MEDICARE right away to see if your situation qualifies for a Special Enrollment Period.

Do I have to enroll in Part B if I am still working?

No, you can delay Part B if you are covered by your employer's health plan and that plan is considered creditable coverage. However, you must enroll within eight months of leaving your job or losing coverage to avoid the late penalty. Check with your employer about whether your plan qualifies.

Can my spouse enroll for me online?

No, you must enroll yourself using your own Medicare.gov account or by calling 1-800-MEDICARE. Your spouse can help you gather documents or sit with you while you enroll, but the enrollment request must come from you or be submitted with your signature on a paper form.

What if I do not have internet access to enroll online?

Call 1-800-MEDICARE, mail Form CMS-40B, or visit your local Social Security office. All three methods work just as well as online enrollment and do not require a computer or internet connection.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.