How to sign up for Medicare

Say you are leaving a job at 68 and you need Part B. You cannot finish the application on your own, because one form has to be completed by your employer. Their calendar is now part of your deadline.

How do I sign up for Medicare?

Medicare enrollment runs through the Social Security Administration, not through Medicare. Signing up for Part A, Part B, or both means contacting Social Security by one of three routes: online, by phone, or at a local office. Medicare.gov points to the online route first, describing it as the easiest and fastest way.

Which route makes sense depends less on preference than on your situation. Someone turning 65 with no other coverage has a simple path. Someone leaving a job at 68 has a form that another person has to fill in. Those are covered below.

If you or your spouse worked for a railroad, you are in a different system. Visit RRB.gov, or call the Railroad Retirement Board at 1-877-772-5772. TTY users can call 1-312-751-4701.

Social Security or Medicare?

Applications go to Social Security, even though the program, the website and the card all say Medicare. That split confuses people daily and reasonably so. Medicare.gov is where the options are explained; Social Security is the agency that accepts the enrollment and holds the record of it.

Getting this wrong usually costs time rather than money. You call the wrong number, wait, and get redirected. But when you are inside a seven-month window, time is the thing you are spending.

Can I sign up online?

Applying online at Social Security is available and is the route Medicare.gov recommends first, describing it as the easiest and fastest way to sign up. It is also the route that captures any financial help a person qualifies for at the same time, rather than as a second application later.

You create a secure my Social Security account to do it. If you have ever checked your earnings record or an estimate of your benefits online, you may already have one.

Online is not the only route. If your situation involves a form that someone else has to complete, part of your application travels by fax or mail regardless. Completed forms go to your local Social Security office by fax or mail.

Am I automatically enrolled if I get Social Security?

Yes, if the payments started at least four months before your 65th birthday. Social Security enrolls you in Part A and Part B without you filing anything, and your card arrives on its own. If no payment is arriving today, nothing is filed for you and the application in this article is yours.

So the condition is a payment, not an age. Turning 65 triggers nothing by itself.

Whether you are enrolled without doing anything turns on one thing only.

Your situation at 65	Are you enrolled automatically	What you do
Already getting Social Security benefits	Yes	Watch for the card
Not yet claiming Social Security	No	You apply yourself

The second row is where the penalties come from. Planning to claim Social Security later means no automatic enrollment, and the first sign of trouble can be a bill.

Whether you are enrolled without doing anything turns on one thing only.

Two other pages ask this from their own angle, whether you qualify at all and what the calendar does if nobody files for you. All three start from the same test: is a payment arriving today.

What do I need to apply?

What you need depends on which of four situations applies to you, and they are not equally simple. Some people are enrolled without filing anything at all, and some have to apply and prove things about their working life. The four are set out below.

Every straightforward case is entirely online. Every complicated one requires a form that travels by fax or mail, and one of them cannot be completed by you alone. That pattern is the useful thing to see before starting.

Turning 65 and signing up for both parts, or just Part A. Apply online at Social Security. This is the standard path and the simplest one.

You already have Part A and are adding Part B because you are losing job-based coverage. You apply online, and you also need form CMS-L564, which your employer fills out. That is the part to start early, because it depends on somebody else's calendar rather than yours.

If the employer cannot complete it, fill in Section B of the CMS-L564 yourself as best you can, but do not sign it, and send proof of your job-based health insurance instead.

You already have Part A and want to add Part B, between January 1 and March 31. Form CMS-40B, sent to your local Social Security office by fax or mail. This route is only for people to whom none of the other situations apply.

You missed your chance at 65 because of an exceptional condition. Form CMS-10797. These Special Enrollment Periods only apply in certain defined situations, so check that yours qualifies before relying on it.

When will my card arrive?

A welcome package arrives after enrollment, containing the Medicare card and the Medicare Number printed on it. That number is the gate to everything downstream: creating a secure Medicare account on Medicare.gov, joining a plan, or buying supplemental insurance. Coverage starting on a date is not the same as being able to use it.

What arrives afterwards matters more than people expect, because one number on it unlocks everything else.

After you sign up you get a welcome package with your Medicare card and your Medicare Number. You need that number to create a Medicare account, to join a plan, and to buy supplemental insurance, so the package is not junk mail.

Two routes are worth knowing if the ordinary one does not fit you. Completed paper forms go to your local Social Security office by fax or by post. Railroad workers go to RRB.gov instead, on 1-877-772-5772, with TTY on 1-312-751-4701.

There is also a separate form for a separate job. Adding Part B when you already have Part A, in the window running January 1 to March 31, uses form CMS-40B.

What this means for you

Medicare enrollment is a Social Security transaction that happens to carry Medicare's name, and the route you take decides how long it takes. Online is fastest for the simple case. Any case involving an employer form runs on somebody else's calendar, which is the part to start first.

Go to Social Security, not to Medicare. One is where you learn; the other is where you enroll.

Online is the fastest route for the straightforward case.

If a form needs your employer, start it first. It is the only step whose timing is not yours.

Wait for the welcome package. Your Medicare Number is what unlocks everything after.

FAQ

Do I sign up at Medicare.gov or at Social Security?

At Social Security. To sign up for Part A, Part B, or both, you contact the Social Security Administration, even though the program is called Medicare and the information lives on Medicare.gov.

The clean way to hold it in your head is that Medicare.gov is where you learn what your options are, and Social Security is where you act on them. Getting this wrong usually costs time rather than money, but time is exactly what you are spending when you are inside a seven-month enrollment window.

Medicare.gov states it plainly: to sign up for Part A, Part B, or both, you contact the Social Security Administration. Applying online there is described as the easiest and fastest way, and it is the same account you would use to check your earnings record.

What is the fastest way to sign up?

Applying online at Social Security. Medicare describes it as the easiest and fastest way to sign up, and it is also how you apply for any financial help you qualify for at the same time.

You create a secure my Social Security account to do it, which you may already have if you have ever checked your earnings record or a benefit estimate online. If your situation requires a form that someone else completes, part of your application will still travel by fax or mail.

You create a secure my Social Security account to do it. If you have ever checked your benefit estimate online you may already have one, which removes the slowest step before you start.

Which form do I need?

It depends on your situation. If you are turning 65 and signing up for both parts, or only Part A, you apply online and no separate form is involved. If you already have Part A and are adding Part B because you are losing job-based coverage, you need form CMS-L564, which your employer fills out.

If you already have Part A and are adding Part B between January 1 and March 31, and none of the other situations apply, you use form CMS-40B. If you missed your chance at 65 due to an exceptional condition, you use form CMS-10797.

One more form exists for a case people forget: if you already have Part A and want to add Part B between January 1 and March 31, that is form CMS-40B. Completed forms go to your local Social Security office by fax or mail.

What if my employer will not fill out the form?

There is a documented route for that. Complete Section B of the CMS-L564 yourself as best you can, but do not sign it, and submit proof of your job-based health insurance instead. This matters because the employer form is the one step in the whole process whose timing is not under your control.

If you are leaving a job and adding Part B, start that form early rather than treating it as the last item, because a slow response from a former employer can eat weeks you did not plan for.

Medicare.gov gives a fallback rather than a dead end. Complete Section B of the CMS-L564 as best you can, do not sign it, and send proof of your job-based health insurance instead. The application still travels to Social Security by fax or mail.

When will my Medicare card arrive?

After you sign up you receive a welcome package containing your Medicare card, which carries your Medicare Number. That number is what you need to create your secure Medicare account on Medicare.gov, to join a plan, or to buy supplemental insurance.

Until it arrives, the decisions that come after enrollment are effectively on hold, which is a practical reason to enroll at the front of your window rather than at the back of it. After signing up you get a welcome package containing the card and your Medicare Number.

That number is the gate to everything after: creating a secure Medicare account, joining a plan, or buying supplemental insurance. Coverage starting on a date is not the same as being able to use it.

What if I or my spouse worked for a railroad?

You are in a different system and should not follow the standard route. Visit RRB.gov, or call the Railroad Retirement Board at 1-877-772-5772. TTY users can call 1-312-751-4701. Railroad retirement runs its own enrollment process, and starting at the Social Security route will send you back to the beginning.

If this applies to you, begin at the Railroad Retirement Board rather than confirming it later. Railroad workers are in a different system for this. Medicare.gov's instruction is to visit RRB.gov or call the Railroad Retirement Board at 1-877-772-5772, with TTY users calling 1-312-751-4701. The enrollment itself still exists; only the office you deal with changes.